Well you described all my symptoms and I was diagnosed with dysthymia years ago. Dysthymia is like walking depression, you can still function, get up every morning and get to work or school but you still feel like crap.

http://psychcentral.com/disorders/sx14.htm

Talk therapy helps, it is good to get some of that stuff out and you actually feel like someone is listening to you. Once you are in therapy you can discuss whether you want to try anti depressants.

I hope you feel better and get some help. Feeling like this really does suck.