You sound depressed (I am not a doctor).
Certainly there's nothing to lose by talking to yours. I am assuming you are in the Northern Hemisphere and it is getting dark and cold. You may have seasonal affective disorder to some degree. A full spectrum light, or just getting outside whenever you can, will help.
Exercise, as PUNKEY pointed out, is a very good idea. And she's right about you taking more charge of your life.
Recognize that a lot of people are in a similar boat. The economy is not truly helping out the younger set; it's just keeping you from utterly failing but it's not really lifting you. And debt sucks
. Do yourself a favor and start spending yours down as well as you can. You'll be a far happier person later in life.
And you're basically where I was when I was about 28. In 1990. Recognize that reassessing your life every few years is pretty damned normal and it's not necessarily a crisis. Rethinking your path is a good thing
I think you've bought into marketing hype a lot, which is interesting because you also know the back end of it (I, too, am in marketing). $98 for a pair of leggings is marketing nonsense. It's also a means of keeping you in debt. Buy good leggings that last and wear them more often than a closet full of 'em. If they cost $98, then so be it - if
they last. If they don't, then buy 'em at Walmart.
And marketing hype is also behind the concept that you must
be married by X age or have kids by Y age or even kids at all. These things also need not go together. The suggestion of adoption is a great one.
And get your eggs frozen if you see really, really oh my God my life will not be complete unless I stamp my DNA on a kid
as a part of your thinking. That should take the pressure off any decisions that your mind is screaming have to be made right now
In 1693, Benjamin Congreve wrote a variant of: Marry in haste, repent at leisure
. 325 years later, that's still true. Think long and hard about marriage. It's not a necessity for everyone -- and a lousy marriage is a lot worse than anything you're feeling now.
If you feel your life and work are without purpose, it can be harder to get up and go to such a job. Then give your life purpose. You are a grown woman. Take your marketing education and put it to good use -- like in volunteering to help your local animal shelter get more adoptions by improving how they present their critters. Or just do some good physical activity, like volunteering at a soup kitchen or building houses.
Explore older music -- there's a ton of it on YouTube or even -- gasp! -- take it out of your local library (another place where you could make a difference). In particular, get into folk, where there's a lot of artifice stripped away. Get into music made by people who you know are known for their musicianship, everyone from Stevie Wonder to Bonnie Raitt to Elton John or Prince or Bowie or Hayley Westenra. Or explore people who are known to have great voices without auto-tune, like Ann Wilson from Heart or the guys from CSN.
Get out and explore your town or city. Find the cheap and free places, particularly places where you can experience art. Maybe the local museum has free Sunday afternoons. You'll never know unless you check.
And hang in there. Like I said, get medical help if you need it. And a reassessment is normal and it is a good thing.
This, too, shall pass.