Panic +apnea + total numbness + brain fog + difficulty waking. Any single one is probably something else, or would only contribute to heart disease.

The cluster of them, particularly with the staggered sleeping while partially upright, there's really only one thing it can be. I might lean panic attacks triggered by bad dreams and apnea, but you don't get total numbness with that, and the postural changes to it reinforce the likelihood of something heart related rather than endocrine, psychological, or it being all offshoots of apnea.

Now, the original cause was likely be apnea, or whatever caused the apnea itself. But once someone starts branching off into that cluster more and more, the higher the chances they're edging into heart disease serious enough that taking a relaxed approach to addressing it is a bad idea.

Obviously, nobody can diagnose online, and I'm not a doctor. But I've seen this pattern way more often than I would have liked. By the time the person is having those start-and-stop sleeps when upright or partially reclined, I would go as far as to say that heart damage is already there, not just incipient.

There's even a non zero chance that the event that brought OP here was a heart attack. Infarction can present weird sometimes, and there's a ton of people that have unstable angina with that complex of symptoms.

Besides apnea by itself is a huge precursor to heart disease. It's like the wheels on the car of heart trouble.

I kinda doubt OP has a major blockage yet, though it's definitely possible that they do, and this event was a final warning sign. But I'd bet good money that they have some blockage going on, if I could afford to bet on random shit online.