Sleepless Nights

For the past, maybe week or so, I've been having bad dreams. Normally the dreams are people leaving me, or me getting killed. And they say if you die in your dreams, you die for real. I know that's not true because in my dreams I've faced my death many times and I haven't died and I never wake up.
In the nights now I'm afraid to sleep because I don't want to see the bad dreams. But the later I stay up, the worse the dreams are. And even if I try to sleep early, I can't get to sleep because now I'm used to staying up later.
I've had to rely on melatonin to get to sleep the past couple of nights because I really just need sleep. I'm always tired. But I think the melatonin makes the dreams worse.
Does anyone know how to stop bad dreams? I really need help.