Welcome! Sorry that you're having this sleep disturbance. There may be some detective work involved before you find the cause, so be gentle with yourself.

The same thing was happening to me for a few weeks but then stopped. Never figured out why. But maybe it was due to having coffee too late in the day.

I do have sleep apnea (in which I stop breathing during sleep). It's mostly due to obstruction, and I use a machine to keep the airway open. But I still stop breathing sometimes, and I figure I might also wake up in a panic at these times.

Too much sugar right before bedtime can cause me to wake up too early, too, because (it was explained to me) my blood sugar crashes. Low blood sugar makes me jittery during the day, and I feel the same way when I wake up at 3am sometimes.

Good luck!