Depression& Antidepressants ?

For the past couple weeks, I've noticed my depression coming back, but the past three days I have been crying over everything and I just want to sleep forever. I have no desire to do anything, I just want to lay in bed and cry. I'm in a very perfect, healthy relationship, so that isn't the problem. I really can't pin point what is causing this. Has anyone ever been on antidepressants ? What is the best one? I need help, school starts next week and I just want to be happy again.