Help! Panic attack when asleep?

Basically I've been having sort of like panic attacks in my sleep.. or sth else, I really don't know.

I would go to sleep like I normally do, but by the time I try to wake up, I would feel like I couldn't move or breathe or anything really, and then I would try very hard to get out of that state, then I'll have a few seconds of being aware of my surroundings, I would tell myself it was only a bad dream, then I fall back to sleep again or faint I have no idea, and I'll wake up again facing the same thing - that I cannot move or get up or breathe.

Until after a few times, I'll finally wake up being super scared. It's been happening for a while and got worse this week.

I was previously diagnosed depression & anxiety, and currently on Mirtazapine. I was feeling so much better and stopped having panic attacks, until these 2/3 weeks.

Also just booked doc appointment, but if anyone ever felt the same or know sth about this, please help:(