Does anyone have any advice on what to do? He keeps doing loads of tiny pees everywhere - is that normal after having a catheter in? At what point do I phone the vet? He seemed OK before we went to the vets so I'm totally confused as to why he's still peeing blood. I'm really scared that I'm going to lose him. 
I think there is often irritation caused by having the catheter in. My cat Ben still hadnt urinated properly when he was sent home, but my vet felt he would do better at home in familiar surroundings, and for the first few hours at home he just lay in a cardboard box, and was dribbling a bit of pinkish urine, but not weeing properly. He did go to the tray a couple of times, but didnt seem to be weeing properly, so I watched him like a hawk and it was a huge relief when he finally did a proper wee in the tray!
I would say though, if you are at all worried phone the emergency number for your vet, and explain to the vet on duty and he/she will be able to tell you if you need to bring him back in or whether its normal after such a procedure.
