You poor thing. I know how deeply these things go. I'm so sorry you're having to go through it. Try not to blame yourself. So many times these these things happen because of changes in the other person.
Were you able to find a therapist? I think you need to see a professional and talk to someone. You need help. Most of the time we just can't get out of our depression by ourselves.
Please keep posting here. We care about you.