I am always sleeping?

I'm a JR in high school and all I ever want to do is sleep, and 70% of the time I give in and just go to sleep. I am stressed but I've been stressed before and this issue just started. I don't know what to do, I sleep 10-16 hours a day sometimes. I have no energy to or motivation to do anything!! This is so not normal and I just don't know what to do!