Have been waking up screaming and sitting up in bed. i clearly remember what i said last and the last bit of related to it, but how to prevent it?

Try talking about it: It seems that you remember your dream but your focus is on getting rid of it rather than understanding it. Did you have a recent accident or other disturbing experience? These issues can disrupt our sleep if we try to avoid thinking about them while awake. Instead of trying to prevent them, try to make sense of your nightmare, maybe with someone's help. That may be the best way to stop them.