Think of the consequences of not doing the work. You paid to take the class, right? Or, at least someone paid for it such as your parents. Not doing the work is not getting your monies worth out of the class. It's like paying for food and immediately throwing it out because you don't feel like eating it right now.
Man up! Don't let your emotions limit you. Yes, you're not in a "good mood." So what! Get off your butt and overcome that emotion and do what you need to do in order to get a good grade. Otherwise, what's the point of taking the class in the first place. I mean, if you were in pain or had a high fever, that would different, but not being "in a good mood" is just a pussy excuse! Man up and do the work.