Not an expert, but when you're facing that much stress, I think it's good to have not only pills from a psychiatrist, but therapy from a psychologist, who will help you talk through the things that are bothering you, and help you come up with ideas for combatting them.
I have not found that the drugs lose effect, but rather that my level of depression varies. It can spiral downward in spite of the pills, or it can lift, all by itself. That's where the talk therapy helps.
I don't regard antidepressants as a dependency, but they sure do help when all I can think of is suicide!