Hey girl, I was in (almost) the same boat as you 3.5 years ago. Long term goals planned with an ex, moved 300 miles away to end our short-term LDR, relationship crumbled immediately and I was left without a place to live in a city where I knew only a couple people. The only difference is that I had thankfully secured a job before moving away. Shit is tough, I'm not going to sugar coat that; depression took over and I made bad choices, but I'm better now. But enough about me. Let's figure out what we can do to improve your situation.
I really want to get out of here. I feel like staying here in this town is suffocating me. I am incredibly miserable, but at the same time terrified of what might happen to me if I leave.
If you pick up and leave for somewhere else, you'll probably still feel better for trying than suffocating slowly in your hometown. At least, tell yourself that while you get the courage to leave. If you're not happy where you are now... you never will be. Is your relationship with your parents good? If you absolutely fall on your face away from home, will you be able to come back "home"? I think it's pretty rad that you were able to move back to your parents' house; being 25 and living at home isn't unheard of (at least where I'm from).
Getting out is going to require money that I don't have, and I don't know how to get.
Defer those loans! Hopefully you're not paying those back now; wait until you get a job. Lie on your resume if you're over-qualified. You don't have to list every accolade, just list whatever you think would appeal to the hiring manager. Do you you have any work experience? You seem to have a pretty diverse range of education and talents, do you know what you want to do with your degrees/certifications/background?
Being completely on my own scares me; I'm also constantly afraid that my Bipolar-II will flare up.
Get thee to counseling! If you're afraid of small-town talk, look for online counseling via Skype (it exists, I promise). You had your life uprooted. You had a relationship end. You're overwhelmed. Everything sucks for you right now, but don't let it consume you!
It'll take time and discipline (not just motivation), but you can get out of this. I'm rooting for you!