Just some family issues

I know I just posted something a week ago and got some advice and it really helped. This is different though. I've been having problems with my family, I'm 17 years old. A little background info is that we aren't the richest family and we do have to watch our spendings, I have Cystic Fibrosis and two siblings (age 15 & 9). Anyways that being said I'm kind of being your typical teenager doing my own thing.

One situation I've had is once I had this freshman come and ask me to buy him condoms from the pharmacy we were at, I saw an opportunity and I took it. I spent $7 and told this kid it was $30 (the kid was also white, that's important for later). Anyways my mom notices I'm $30 less broke so I tell her the story. She instantly gets on me for taking advantage of the kid. I didn't agree with it because the way I saw it the kid could've known before hand and wouldn't have gotten hustled. She then brings race into it (I have no idea why) and starts making claims that I'm just a racist pig with white privilege and I'm everything that's wrong with this world. I couldn't really say anything because I don't understand how my mom knowing what I deal with every day with my disease and us struggling financially would call me privileged, or would even state that when I support everyone. I don't associate myself with BLM, LGBT, or Feminist groups much because I believe some of the methods they use are wrong, but I do treat everybody the same and don't disregard anyone for any reason, she's more of the "I don't see color" people and I'm more of an "I respect you as a person and I'm not gonna treat you differently because of it". It still hurt me since it was coming from my mom, and I've spent several nights since up late thinking it's somehow my fault.

The second scenario is where my baby brother wanted his headphones which were in my room, and he came and knocked on my door and asked for them but I was changing so I told him that I'd come out with them in a second. He instead ignores me and comes in my room while I'm naked and I immediately push him back out and tell him to wait for 2 seconds. then he goes crying to our parents that I pushed him. My dad immediately gets in my face, literally his nose is in my forehead and his spit is just hitting my face (He's a pretty high rank in the military so I guess he's used to dealing with things that way.) I try to tell him to take just one step back and he knows it puts my body in a panic but he just continues yelling in my ear and getting mad that I want just a little space and I lost it and shoved him away. he then starts pushing me down our hallway (maybe I deserved it I honestly shouldn't have even touched him and really didn't mean it but my body just panicked). I didn't even get to explain myself he just assumed I hit my baby brother because my brother exaggerated and said I hit him when I just closed my door on him as he opened it.

The last thing is I'm obviously the black sheep of the family. My 15-year-old brother just got a ton of stuff and plays football and plans to play in college (My dad's favorite, his words). My 9-year-old brother is babied by my parents and can't solve anything on his own (My mom's favorite because he's still a baby that just wants to be with her 24/7, also her words). So that leaves me, the computer nerd who's studying Cyber security/Coding and has depression and a life expectancy of around 25-30. My parents don't approve of me doing anything. I rejected getting an allowance because we need the money and I'm ungrateful. I'm trying to get a real job and want to give them 1/3 of my pay to help pay bills and they say I just want to get out of doing chores and take my offer to help as an insult. I don't know what to do. I just feel they take care of me because they are required to by law.

So yeah I do have a therapist I talk to but she was on vacation for a month lol she comes back next week. What advice