Hello Anna,
it is very good that you are curing your depression at your age. I wish I had started so young. Well, antidepressants need patience, lows still happen, but are supposed to be less low and shorter. If not, the psychiatrist will adjust your prescription.
I don't think you are depressed because your are a failure. On the opposite: you fail often because you are depressed. It is how it works, I can see it with myself. So be patient, heal yourself (therapy is fundamental too) and you will not fail anymore, except sometimes like everyone else.

And keep posting here!

The best of luck