OP, you can come back from all of that. Depression, anxiety, drinking, self isolation, and self doubt, I've been there. I'm probably older than you, 32, in a relationship, as dysfunctional as it can be and studying healthcare, with the goal of applying to med school in two years (to become a psychiatrist). I've cut down my drinking (though I use a little pot now), and I'm on Zoloft, which has been great. Working on getting set up with a new psychiatrist.
Here are some of my tips:
Talk to a psychiatrist/psychotherapist. If you need to, get on antidepressant medication.
Take care of your skin. Washing your face in the morning and before bed and moisturizing properly makes a world of difference in how you look and feel, and men aren't encouraged to do this routinely. Do it.
Drink more water. Seriously, people don't enough water, including me. I just bought a $16 Brita water bottle with a carbon filter. Not saying you have to get one, but just hydrating every day in the morning and throughout the day is very important. This past month I've been drinking a lot of soda because my boyfriend drinks a lot of soda, but I've been cutting it out more and more.
Read everything. When you become extremely informed, it can also be depressing because you become hyperaware of all the pain, suffering, apathy, and evil in the world, but at least you'll be a smidge less self absorbed, and maybe it'll inspire you to do something or create something.
Just some thoughts. If you need someone to talk to, I'm here.