First, I would say eliminate mundane causes. It could be anxiety, just your imagination, etc.
If you’re sure it’s metaphysical, you can cleanse frequently and/or set up wards. there are lots of ways to do that.
I have found this charm effective for keeping away nightmares:
Get a bowl.
Put rosemary (and/or sage), black salt, and an amethyst crystal in it.
Focus on your goal to have peaceful dreams while assembling it.
Place the amethyst crystal under the full moon every time there is one.There are a lot of factors, and a lot of things it could be affecting this so I encourage you to look into it more yourself. I don’t really have enough information to be able to figure out a solution for you.
THAT IN MIND, it sounds like you might have too many things going on magically that could interfere with each other/ kind of cancel each other out.
Also. I would also be skeptical that the dreamcatcher is effective, unless you learn to the actual, authentic way of making and sustaining it from the native people that it comes from. If you just got your information off of the internet it’s probably wrong.