Hey shellfinne,
My brother have had similar experiences as yours on a regular basis for years. Such as, laying beside his bed stuck on the ground. Along with it he he told me he had trouble with breathing, like feeling short on breath. After a few days I was in his room while he was sleeping and I heard him breathing very heavily so I woke him up and told him that and he didn't know it. But he went back to sleep and I went to bed as well a bit later. The next day we talked a little and I told him when he gets it he should just relax and calm down and breath in slowly instead of taking full heavy breaths. He hasn't had any trouble with breathing, sp, or nightmares ever since.