Please don't feel you are stupid and don't belong,like Gettingby said everyone is here to listen to you and help where possible. I was feeling like that myself last week, but after some convincing from some beautiful new friends on this site, I decided to keep posting. You should take Gettingby's advice and contact the Human Services, they will help you.
Is it possible to move from that place and go somewhere where it is more affordable, more jobs and better prospects? Don't worry too much about your friend's crazy girlfriend, talk to him and tell him what is going on with her being jealous, he knows you and he will know you're not jealous. Tell him how you feel about him going away, he won't think you're blaming him. You are keeping too much bottled up inside and you need to tell him.
I don't think any college degree would be useless, surely there must be employment agencies that you could go to, like I said maybe somewhere different, especially if your friend is leaving maybe you should think about it also.
There is something much better for you out there, you just have to pick youself up, dust yourself off and go get it.
Please keep in contact with us and let us know what you decide to do.