[Everglow.]

Nightmares are awful, especially the ones that are really disorienting. I'm sorry you're dealing with that.

Whenever I have a particularly bad dream, the only way I can settle again is to get out of bed and move around a bit to detach myself from it. I always check things are as they should be (e.g. the other night I had a nightmare that my teeth were falling out, so I went to the bathroom and checked they were still there).
I also always keep water handy. I have a thermal bottle so it's very cold. I find cold water helps to ground me. Sometimes if I'm particularly disoriented or anxious I will spend some time sitting on the side of my bed doing more grounding techniques too, like touching the cold wall, or bouncing my leg. It could help to remind you that you are here, and not there anymore.

Before bed, it's always good to keep away from any possible triggers, such as intense TV or films, books with triggering content etc. You could try inventing a new bedtime routine that is relaxing for you. For example, doing some skincare, lighting a candle, journalling, or even taking a relaxing bath to wind down before sleeping. Lavender can also soothe sleep, so you could try a sleep spray for your pillow, or some essential oils near your bed.

If the nightmares and anxiety continue though it never hurts to ask for help professionally, so maybe you could speak to your doctor/therapist if nothing else is helping.

I hope this helps and that the nightmares stop soon!