Fashion advice for a very short, fat ginger?

I've been looking all over the internet for fashion advice for petite-plus women and I'm finding it much harder to find clothes in my size. Because COVID19 makes it harder for me to exercise and shop, especially since I barely know my size anymore, I've gained about 40 pounds since I started my bipolar medications at 26 years old. I went from a healthy 125 pounds to being 160 pounds and the doctors say I'm "obese", but my boyfriend thinks my curves are beauty marks and I am NOT fat at all. Still, my jeans, which are all size 12 petite, are now getting way too tight on me, that now I think I'm a size 14 petite, that now I'm starting to realize I'm a "fat fat fatty bitch". I know that's a put down term, but it's aggravating my sense of style.
When I put on clothes in my closet, everything looks weird and I actually look fatter in the mirror. I want to hide my disgusting "beer belly" and look taller. I've looked up so many articles on women's fashion, and yes, I've seen LOADS of girly movies that involve fashion and designer labels- Devil Wears Prada is my favorite because I'm Anne Hathaway's biggest fan and she killed her performance as the struggling assistant to Miranda Priestly, Andrea Sachs. I'm also a cosplayer and a crochet fashion/ costume designer, I just crocheted a PERFECT butterfly cloche hat in beautiful vibrant colors for Valentine's Day- my incredible boyfriend is taking me away for the weekend for the holiday of romance by spending a night in a cozy hotel and having a four course fondue dinner at The Melting Pot, a five-star award winning fondue restaurant in Maryland. And yes, for that restaurant, even before COVID19 happened, reservations are ALWAYS required. They do a special fondue dinner event for romantic couples every year for Valentine's Day, and this will be my first time going to that special swanky restaurant.
Though it will be my boyfriend's second time going there, it will be his first time in a couple decades, and it's his first time seeing the new remodel of the restaurant- they renovated everything a few years back somewhere around 2017.
Anyway, I feel like my tastes in ladies' clothes are fading because I'm drawn more and more to rock band shirts, turtlenecks, and Doctor Who, fantasy, and nerdy fandom shirts with superheroes and sci fi on them, much like my boyfriend. I also don't have any work clothes left because hardly anything fits anymore- I got rid of all of my work pants for office jobs. I did go buy some new slacks and a new suit jacket that "hopefully" matches together because both are solid dark colors that are on the gray-black color scheme, perfect for a job interview. I also bought a lovely pink floral dress, a new coral sweater that is soft and squishy, and a flowing dull pink skirt with vertical pleats from H&M, which I love. I love anything with vertical stripes or pinstripes and I love the color pink.
However, I don't know how to dress this fat body of mine. I feel like there's nothing I can wear that will make me look my age (I'm 32, but my face makes me look like a teenager), but will also make me look thinner and taller without washing out my face. The internet is telling me to wear nude colors on my feet- I hate nude colors like tan, beige, gray, and taupe- they make me look like a ghost. I have red hair, which means my skin is whiter than porcelain. I feel like anybody who is not white is prettier than me- Asian, Latina, Hispanic, and Black women look SO much prettier than me, it's horrible what my low self esteem is doing to me. I hate being a white chick being related to Irish, German, and British people.
I'm no taller than 5 feet tall, I'm exactly 60 inches tall. There's no way I can get any taller. I put on clothes and I look like a 12 year old fat kid in middle school. I want to look more mature and charming, without losing my confidence and my love of certain colors. With gingers, we hate the color yellow- yellow is my enemy because any yellow clothing I wear makes me look like I have Hepatitis C. I prefer bright and pastel colors like green, blue, purple, pink, red, silver, champagne (the only yellow colors I appreciate are metallic ones, that includes champagne and gold), and pairing them with normal earth tones like chocolate brown, denim, black, white, tweed, honey brown, and brown herringbone. But I still feel a little on the frumpy side with my clothes, but I'm not a complete disaster like my grandmother, who chose to wear clashing colored animal prints on her mismatched shirt and pants to my dad's funeral. My grandma is a psycho for wearing things that don't fit and clash terribly and never worked for an 80 year old. She wears incredibly inappropriate things, and she thinks I'm the weird one, which is why she hates me.
Other than that, the articles constantly contradict each other and they also suggest to buy from very expensive places. I never shop at Nordstrom, I've never even been inside Saks Fifth Avenue, and DSW, forget it. I buy clothes usually at Walmart, Goodwill, H&M (clearance rack and their sales, normally), Boscov's (clearance, rarely), Old Navy (only if it's clearance or on sale), and very rarely, Target, because I still have a money shortage, I have no income and no job, and I dropped out of college to take care of my widowed mom during the grieving process. I used to shop at Marshall's and Ross, but they're basically gutted because they have no new clothes for women, they're always out of everything, their return policies are a sham, and they never have my new size. I feel like I don't know what to look for anymore. The dress I bought at H&M is fantastic, but it's more of a spring dress and the V cut neckline is a little too low on the plunge side and I don't want to show my boobs too much, or at all. But because The Melting Pot is a very nice place, I don't think the pink fuzzy sweater and the pale pink skirt will be a good match for dinner either.
The dress code attire for Melting Pot is specifically "business casual", which I understand means, dress nice in nice pants, a nice blouse, or a flattering dress for ladies, but t shirts and jeans are not allowed. I've already helped my boyfriend Alexander pick out what he's wearing and I gave him a few simple tips on how to dress for men- he's wearing slacks, a button up herringbone shirt I picked out which looks UNBELIEVABLE on him, and a really cute dinner jacket from the men's section of Macy's, Ralph Lauren, on sale. He's got plenty of ties, so he's just going to pick one because there's no such thing as being overdressed for this date.
I want to look just as lovely for our date, but I also want to wear something in the color red or pink for this special holiday date to celebrate our relationship. But I feel like a soft cozy sweater and a skirt won't do it, especially since I have to wear pants anyway- it's going to be a low of 23 degrees outside on Sunday night. And since it's Maryland, it's supposed to snow this week. Maryland is notorious for bad winter weather in February, the most disgusting.
Anyone have any suggestions on what a fat, curvy, 'petite' woman with red hair should wear at all?