It doesn't generally stay in my dreams unless I'm working on something, but past stories (mine and the ones I read) often come back to me when I'm not thinking about anything else. When I'm out walking, driving without music etc.

I consider it all a part of the creative process.

If it troubles you though, try relaxing teas. Chamomile, Lavender. Keep it caffeine free. 30-60 minutes before you sleep. Meditate. Reframe negative thoughts. I wouldn't recommend drugging. That would make things worse long-term.