Is it normal to have constant nightmares

I have these nightmares of falling. I will close my eyes and then I will start to fall asleep then. I start to fall. It's so realistic it scares me to death! I jolt forward and start gasping for air. One time I had a nightmare that I was rolling on the edge of a cliff. Then I started to fall further forward and I he'll off my bed. Other times if I don't have falling nightmares I have nightmares about a loved one dying and it feels so real like it actually happened. If not that I wake up covered in sweat. I'm nervous and afraid to fall asleep because u don't know whats gonna happen next.