Talk to Psychiatry on Depression

I think I have depression. I don't find any interest in anything. I don't feel relax doing anything. most of the time I am sad thinking , why you are wasting your time, if I study 6 hrs still I think I did nothing , I should study 12 hrs or more, when I do anything after I think why you did that and you wasted time. I don't even get interest in doing my favourite things like football, computer games, and watching movies. And when I do something , my thoughts go here and there , can't concentrate on the current thing , which also weaken my memory. Please suggest . Thanks waris