Ok, so this will sound reeaaallly wiered, but I want to know why this is happening...

I was in the shower the other day, and my leg started shaking violently on it's own!!! I freaked out!!..I mean, I'm just 16!!!!! When I put some pressure on it, it stopped...
So I want to ask, is it because of some vitamin or protein deficiency? Or is it just a sign for me to say goodbye to life??
I know I sound stupid, but I don't know how to ask without making a fool of myself! T-T