What's wrong with me?

Recently, I haven't been bothered to do anything. I've fallen behind on schoolwork and am getting Ds in my mocks despite the fact that I used to love school, skipping showers, not putting makeup on in the morning... I keep reading I could be depressed, but I'm not a very emotional person - I hardly ever cry or overthink, in fact I often try not to think about things too much.  I just have no willpower anymore.