I keep waking up screaming?

For years now I have been talking in my sleep and occasionally started screaming and thrashing about. I'm 19 and think its a serious sleeping disorder. is there any way I can stop it? My parents and sister get mad at me when I scream in my sleep but I can't help it. and I dont even remember what im screaming at most of the time. please help me, I wake up crying too, My boyfriend is worried too...