I think that since you're asking, there's a good chance you might be depressed. I drop piles of weight like that when I'm in a mild to moderate depression -- and sometimes I'm too busy to even have time to notice that I'm not feeling like myself. It's not until I get into the way-down deep depression that I realize what's going on.

You should go talk to a professional before you slip any further. I know how exhausting a busy schedule can be. Your mind and body can only keep that up for so long before you get totally worn out and exhausted. You probably haven't been taking much time for your SELF -- and that can be really tough on your well-being. Is there any way you can take a little break and do something enjoyable just for yourself? And go to your doctor and talk about this. I hope you're feeling better soon.