You have to remember that I was eight when I had my appendix out - 48 years ago! - so medical techniques have advanced markedly in that time. I've got a three-inch scar to show for it, and it seemed a not-uncommon thing back in the early 70s.
I vaguely remember the digestive issues at first, but they resolved themselves. Mum bringing in tinned salmon sandwiches on the bus was a favourite
By all means take the anti-biotics for the seven days. Just keep as near as is practical to the bog.
Think about this: the scare stories we read about in papers and the like are when it goes wrong. It is so rare it's deemed newsworthy. Nobody ever writes "twenty surgical procedures were carried out successfully today." I'm scared of surgery too, as I too am one of those people inclined to believe "well, bad things
have to happen to
someone." Sometimes they do; but again, that doesn't mean that
you are pre-ordained to be one of them.
Enjoy putting your feet up, watch some trashy telly or listen to some music and make sure the bog ain't too far away.