I have suffered HA for years. Sometimes so severe, I almost lost touch with reality. I am much better now, but truly, I get where you're coming from.
About 10 years ago, I needed an urgent op in the middle of the night, so no warning at all. My HA was at it's worst and I was almost hysterical with fear at the thought of a GA. I didn't think I'd survive it...I'd have a terrible reaction and die on the table etc. etc.
The team operating on me had to go off for a more urgent case just as I was about to be put under, so I had an hour's wait in the little pre-room being looked after by a male nurse. That man saved my sanity that night.
He'd been nursing in operating theatres for about 15 years and he told me that the only people who ever die under anaesthetic are people with very, very serious conditions....people gettig quadruple bypasses etc, and even then it's rare.
He said that chances of an otherwise healthy person dying are so exceedingly slim, most professionals will never see it happen in their entire careers.
Reactions are uncommon....but when they do occur they are nausea and headaches afterwards, not death.
I will never forget his words to me: "You have my personal guarantee that you will not die under anaesthetic". He meant it, and I believed him...so should you.
You will be fine. You might be a bit pukey, headachey, drowsy afterwards....but it is a virtual guarantee that you will be fine. One day old babies have GA, as do 99 year old grannies...and generally, they are absolutely fine. Anaesthetics are very, very safe these days.
In terms of how it feels being put under....it's a piece of piss. No different to falling asleep. In fact, it's quite an enjoyable sensation.
Have you considered that your HA may actually be because you are a lone parent to your son? I was also a lone parent with one son and my terror of leaving him alone in the world played a large part in my HA.
CBT can help enormously...something to look into?
Good luck, and let me say again....you WILL be fine :)