~Doctors only~ I have a seizure thingy?

Ok so im going to try to make this as short as possible. So im 15 years old and i have to wake up at 6:30 every morning to go to school. Some nights when i stay up around 12ish i wake up and im super tired (obviously) But the thing is when im tired like this i begin to twitch. Like its almost as bad as a seizure, when im holding something i would just throw it across the room or onto the floor (involuntary) when this happens I ind it really hard to keep my eyes open no matter how hard i try. Sometimes the "twitches" get so bad i fall to the floor making this really weird noise. Help whats happening to mee?!?!!?