I definitely relate to this. I start more projects when I am not depressed and then cannot keep up with them when I am. Half of the month I am very productive, the other half I really struggle to get even basic tasks done. I told my psychiatrist that I try to make up for what I fell behind on when I am feeling better, although I guess sometimes I just drop the project. A couple months ago I was excitedly planning a trip with a friend, practicing my Spanish for the trip, watching documentaries and everything. Then my hormones hit and I got all discouraged and haven't gone back to practicing.

Do you have any idea why it's getting harder to bounce back? Are you feeling perhaps "why bother?" if you're just going to hit another depression? I know it can make me feel a little defeated, personally. Something that might help is to remember that just because you have stopped being productive now doesn't mean the work you put in before doesn't count. Did you learn anything in taking your French classes? If so, that is something. You can always go back to it later. Being hard on yourself might only discourage you further. I think if we internalize that we will never finish anything, it can become what we expect of ourselves. Perhaps setting up mini goals to celebrate your success could help keep you motivated? If you meet those goals, than you can remind yourself you did in fact do something without quitting.