Who is prescribing your antidepressant medications? It would be important for you to talk to a psychiatrist about your depression, the fact that it waxes and wanes regardless of your meds (this suggests to me that your meds are not as effective as they could/should be), and what you should do about it.
Sometimes psychotherapy with a psychologist can be helpful too, to address negative thinking patterns and any relationship issues that arise due to depression. In particular, most research shows that Cognitive Behavioral Therapy (CBT) is most effective for treating depression.
I would suggest using a combination of these things- medication and therapy as this seems to have the best results for most people.