[ogreveins]

You may want to try sunshine or bright lights. http://lesswrong.com/user/chaosmage/overview/

Other than that I can only think that you're not properly motivated. I don't know much about clinical depression so this may be obtuse but let's assume you were being tortured; burned, whipped, fingernail removal, whatever. Would you do everything in your power to get out of that situation? Well right now you're comfortable. There are no pressing matters and you have pretty much whatever you need from day to day. That emotional inertia that was there when you began working on your startup isn't there. There are also no new stimuli to spur you back into motion. So the only thing you can do is rest until your comfort level with your progress drops enough for you to get back into gear. I don't know, there's a very good chance I'm projecting from my own past experiences.

The only solution I've found which works for me every day is to get angry. Angry about what other people have done that I haven't done. Angry about what other people have that I don't have. Angry about not using my talents to the fullest - not seeing what I'm capable of doing. Angry about being told no, I can't. My progress is fueled by rage and my heart will probably pop by age 50 but I will get my work done. I will never allow myself to be comfortable.

Good luck, whatever you do.