From the headline I was expecting some kind of disaster, broken bones, blown spleen kind of thing -- but, you know, understated.
I won't repeat what everyone else has said, but I applaud your, "calling it a day". Technique, progression, what-have-you aside -- only you know yourself. It is often better to live to ride another day. Any significant (I won't say "major") injury I've ever sustained was on that, "I'll do just one more" run.