Certain dreams make us nervous

Did you had a dream in which bad things happen, u try to save someone but u can't, u try to run but u can't...? Last night i had one of this dreams and while being asleep and visualising the "movie" my heart had an insane rithm that eventualy woke me up for a few seconds. I can wake up and than go to sleep again and continue my dreams, it's a weird thing but..hey..I am weird too:)...So there i were, caught in my dream where i had the most terrifying feeling, I was sooo scared but not for me or my life. I was trying to convince someone not to commit suicide but that person did not want to listen to me..I had this in more than 1 situation...it was an empty elevator...than a train as i remember...but all places were dark, shadows, very very quiet...only us fighting, me shiverring, my heart beating like an exploding bomb and he, not knowing what to do...almost crazy. I can not remember the end...but I think he did it..:( I woke up all messed up, with the feeling that someone close to my heart is not ok...so i guess this is not a good day for science at all..and all I wish is that everyone is fine and I just went to hell and came back empty handed...