I'm so sorry. I am going through this exact same thing right now, as I have had a major depressive crash from mania. Everyone tells me to find something to do that relaxes me, but how can you do that when nothing interests you? I'd like to say I'm just looking ke this when depressed, but I am also like this when manic. The difference is when I'm manic all I want to do is work (we have a home-based business) obsessively work, that's all that interests me even though I know it's not healthy. But again, how are you going to take a break from wotk when nothing interests you?
I wish I had some advice, I don't know right now. I can say I do have a new therapist who has helped me with some of this, but I haven't been able to afford the copays and haven't seen her in over 2 months. A good therapist might help, if you can make it to one. I do like to bake, but i often don't have the concentration skills to make it through a recipe. I do hope you are able to work through this. I've been through this for a long time and i know it's frustrating when people tell you to find something fun to do when nothing interests you. Just try to hold out hope you can make it through this until something changes.