Screaming in my sleep??

In the last week, i have been waking up screaming in my sleep at the top of my lungs twice now. The first time I remember fulling waking up only after my husband woke me up and then last night he woke me up but i do not recall anything. Can anyone give me any insight as to what might cause this to happen?? I lost my voice already from the first time from my shrieking and I kind of need it :) thanks!