Trouble concentrating and remembering.

I've been extremely anxious since I was 12 years old. But back in August 2017, I slipped into major depression. I couldn't sleep for days and didn't want to do anything. Everything seemed to be a burden and in November 2017 I was diagnosed by a psychiatrist for Dysthymia. He prescribed me Fluoextine and Dosulepin. It really helped in improving my everyday mood. Finally I could perform everyday work. But I still can't learn anything easily (before that I could understand and learn in just one or two reads). I keep forgetting things all the time. I lose track while talking and forget what I just said or heard. When I told my doctor he increased the dosage. But nothing has improved. It's crucial time in my life. I am preparing for UPSC CSE and my career depends upon it. I need help !