I am so sorry you are going through this. I have lived large swathes of your story and the pain, frustration, and insecurity you're experiencing are emotions I am all too familiar with battling. I can tell you it is absolutely not hopeless, that it will be okay, but that, I found, only goes so far when you've got no idea where to start.
Rather than giving you a wall-of-text prescription, I have just one suggestion based off reading your post. Ever seen a coloring book for adults? Here's one example, and you can find others or even Google pages you can print yourself: http://www.amazon.com/Adult-Coloring-Book-Relieving-Patterns/dp/1941325122
Buy a book (or print some pages), get your favorite coloring media out, and start coloring. Seriously. If you can do it on a regular basis, that's even better. Just...do that. Start there, and see what happens.
That's amazing! Having your own car is a huge first step :D
Here's some to take a look at sometime. They're really relaxing.
It's great that you're saving up some cash though, that's really good progress you're making :)
Yea, I'm doing Secret Santa for the second time this year and I'm looking forward to it.
I was thinking of something focused specifically on self care, like coloring books, hot chocolate, self improvement books...but I guess a exchange focused on people struggling with anxiety and depression might be weird. Whatever, I'm just disappointed I can't suggest and vote, like I've said.
Adult coloring books have actually become popular recently (for example https://www.amazon.com/Adult-Coloring-Book-Relieving-Patterns/dp/1941325122).
Seems like adult coloring books are now a thing: http://www.amazon.com/Adult-Coloring-Book-Relieving-Patterns/dp/1941325122
Learning to play a musical instrument
Making chainmail
Painting
Sculpting
Carving
Adult Coloring Book: Stress Relieving Patterns is the one I got. There are SO MANY.