I'm very sorry. That's an extremely frightening experience.

I had a period of time years ago when I was having panic attacks waking me. Thankfully that doesn't happen anymore for me. I don't know what causes them but the problem is they can disrupt your sleep patterns because you become frightened they'll happen again. I couldn't go back to sleep straight away because of the way I felt, so often would get up for a while or even have a relaxing shower and then try to sleep later.

I hope you start to feel calmer soon.
take care of yourself.