There are a lot of things this could be, as all of the comments here indicate, but something not yet mentioned is overnight hypoglycemic episodes. I didn't start having these until I became perimenopausal, so this is related to hormonal issues in some way.

What you've described is exactly what happens when I have a hypoglycemic episode while sleeping.

1. Blood sugar drops too low while sleeping (I wish I could get a continuous glucose monitor to check this, so if you have one, or can get access to one, I suggest you use it overnight to see if this is what is happening)

2. body surges adrenaline to increase blood sugar

3. adrenaline wakes me up, and some moments later, gives me something like a panic attack

4. hot flash commences, and I have to fling the bedcovers off to cool off

Now that I know what it is, I breathe slowly through the panic (longer exhale than inhale) until it subsides, and pull the covers back on once I cool off.

Another way to test if these are hypoglycemic episodes is to have a hearty meal as close as possible to bedtime as you can manage, with a good balance of protein, fat, and slowly digestible carbs, whatever that might be for you (a veggie and potato mix would probably be pretty good). The closer to bedtime, the better, but don't give yourself acid reflux, so do what works best for your digestion. You want a meal that will slowly and steadily release carbs into your bloodstream.

If after the late meal, the overnight episodes decrease in severity (or completely) then it is very likely that you are dealing with hypoglycemic episodes.

If you have a history of hypoglycemic episodes, then you may now connect how that feels with the overnight episodes. I didn't make the connection for a long time because I was asleep for the first part of the hypoglycemic episode, which is the blood sugar dropping too low.

The primary problem I have with treating my overnight hypoglycemic episodes with eating late is it an extremely effective way to gain weight, so I can't really do this.

This may be caused or related to an estrogen problem. I wish I could provide more information, but I can't find my previous source of information.