Sorry you're dealing with such overwhelming feelings, Vinsanity. I have a long history of clinical depression, plus some anxiety issues, so I have a clue what you're talking about.
It's really good that you've sought help. My suggestion would be to put much more emphasis on talk therapy than drugs. Don't get me wrong, I have nothing against psychiatric drugs, but they cannot 'cure' you (unless you're deficient in something that they're replacing). Think of them more like a bandaid you use to help make you feel better and get you over the hump while you're working with a therapist to get to the root and, hopefully, resolution of the real issue(s).
Sometimes things we've been doing right along without problems just become too much. Usually it's a cumulative effect--you're not really aware that things are building up, and then, bam!, you're like, WHAT JUST HAPPENED?!
Don't despair, though. Even if it turns out that you have something like clinical depression or you're bipolar, there's plenty of help available.
One thing I absolutely want to emphasize is DO NOT ISOLATE yourself. You may feel like pulling into a cocoon and withdrawing from people and places, but that's rarely a good idea. The more you isolate the more you have time to think about how crappy you feel. It's a dangerous and vicious circle. Even if it's hard to go out or have friends come over, even if that provokes anxiety, it's actually still better than withdrawing.
Do you have a close friend or relative you can talk to openly about this? Someone who won't make you feel like you're being judged, but will just listen and be supportive?
Also, don't forget that there are tons of places online to seek support and camaraderie among others dealing with similar issues.
Good luck. I hope you feel better soon.