I had an ERPC after a missed miscarriage, which I understand is pretty much the same thing, and for reasons I don't understand I also became convinced I was going to die beforehand. I've had general anaesthetic before, I don't have any health anxiety, I don't really know where it came from. Luckily I was only waiting 48 hours before the surgery so it was really only the night before I struggled.
The tablet just softens the womb opening if I recal, it would be hard to have a reaction to it. The actual procedure is very quick, so normal risks from anaesthetic- which itself are vanishingly low- are even less because of that. My husband basically had time to go get a coffee before I was back up.
It's stressful, regardless of the reason. Your brain will be whirring and you'll have lots of anxieties that are turning into this one fear. Your hormones are also all over he place. I found as soon as I got into the hospital I was fine- the nurses were so competent, there were so many other women having the same thing. It's the waiting that's the worst.
My advise would be to try and distract yourself. If you need to, get some anti anxiety meds for now. But you'll be fine, and it's ok to be scared. Just know that the risks really are almost non-existent.