Bad dreams... :(

When I was pregnant with my first I never dreamt bad dreams just vivid dreams about dragons or my family nothing too crazy.  With my second I've been dreaming scary dreams, I can't sleep I wake up terrified.  I dream evil dreams and wake up and hardley ever fall asleep again. The only times I don't dream is when I take Unisom (sleeping pills OB prescribed) but I don't want to take them every night.  Anyone else have this problem?