Aloha Joe
Contributor
Talking this over over a beer or two... or... with a good buddy / companion that you can do that with... may help putting things in perspective.
There is nothing wrong with feeling some guilt or questioning and wanting to improve once actions after the fact if only one could. That's normal. There is nothing wrong with learning from it or getting motivation from it. But there is a lot wrong with letting it eat you. Don't let it!
I am not saying at all that you made a mistake, but I am saying that only those that do nothing make no mistakes. I think you are already thinking the right things. You seem to plan to keep doing and to learn how to get better at the doing and that to me is the right thing. Infinitely better than deciding to be done with doing. So, keep doing...
Addendum: I bet it helped some to write this up here on SB, but it also took guts to do that. Kudos.
I think part of why this is so hard is that this is a solo trip. I visited a few dive shops and told a couple people what happened and it helped a little to talk...until the scene repeats in my head.