What causes vivid nightmares?
It means the quality of your dream is not good. People only remember their dreams when they cannot sleep too well. (Worse you sleep, more vivid the dreams will get.) It’s totally normal, has a scientific explanation (look above), just try to don’t think about negative things, your problems when you go to bed (and also don’t think about your dreams!), try to have regular sleeping hours, and make sure your room is dark and noise-free: when something makes a noise that you can hear it will make you wake up at some level. Not really wake up but will get the quality of your sleep lower.
