Yeah, I know what you mean. I've just recently gotten out of a rut (hence why I posted my great week blog), but I can definitely sympathize with you there. I felt like things I used to enjoy just weren't enough to keep me getting up in the morning and I dreaded every moment I had to be responsible. But I think I just had a case of the winter blues or something.
Maybe that's what you're going through too? Just a bad case of the lows. Which, oddly enough, is very normal! That reminds me though, is your depression seasonal?