Mark, it sounds like you were definitely not right on the day so i wouldn't try and over analyse it to be honest, though if I'd started peeing blood I would have definitely stopped!! Best thing would be to get down the docs and talk about the blood in your pee then go from there. A massive "well done" for the improvement in your weight and fitness.
As for the ACL, I'm typing this with a bag of frozen peas on my knee having just done the "triad" of MCL, ACL, and meniscus in a ski fall so there won't be much running for me for a bit. I agree that most sports can be done without the ACL though current studies apparently do predict a higher probability of arthritis in later life without a repair. I'm going to have mine done, assuming the MRI confirms the damage, (the manual tests seemed pretty conclusive) as I want to ski again, though I have a mate who skis quite happily without ACLs in either knee! Bizarrely my wife managed to snap BOTH her acls in January and has her first op tomorrow so we'd done lots of research before I managed to do mine!!
Good luck with the op and I'm sure you'll run a marathon to your satisfaction soon.
Edited: 25/04/2012 at 22:13