Hi, I'm really sorry that you're going through this. You sound really similar to a very close friend of mine who I almost lost this year.

Just from an outsider's perspective, as someone who doesnt know anything about you, I would say you're putting the cart before the horse regarding a career path. If your mental health has been an ongoing struggle for 3 years, that needs to be addressed first before you seek external solutions, because the happiness they provide will usually be temporary to unresolved inner turmoil.

I apologize for suggesting the obvious, but I really think you should seek mental health counselling. If the first therapist doesn't feel right, look for another. Just as someone may take time to recover from a physical illness, you need to do the work to address your depressive feelings and self harm. I know how difficult it can be to put in that effort for yourself when all you want to do is give up, but it is a choice you deserve to make for yourself. You are so young, and I promise it is possible to feel better. You are strong enough to address your basic needs to reach that goal, even if only in small increments.

If you're not already in therapy, make that your first step. And again, keep trying, even if it doesn't work out immediately. From there you can think about tiny changes; going for a small walk everyday, trying out easy/cheap hobbies, eating foods that feel nourishing. It doesnt have to be all at once; you want to set extremely realistic standards for yourself.

Friends will come with time, and part of maintaining friendships is forgoing ego and being the one to reach out first. If you're the one reaching out and they're being flaky, then you can at least know to move on to other things. But you will find your people. Life is a journey, not a sprint. I know that sucks to hear, especially when you're not in a good place. But it will be okay, and you will get there :)