Cat peed all over my bed!

I came into the room and noticed he was scratching around, and then the smell hit me. I picked him up and his whole bottom half was covered in pee. I took him to the bathroom to clean him up. I forgot the wipes so I went to go get them. when I came back in he was fighting to get out of the door; he is usually never this skittish. There was a giant spot of pee on the bed, there was a lot of it, like an unnatural amount. There was also quite a bit on one of the the blankets, but it could have easily been from the same area. Then there were little bits around the area which didn't soak into the mattress. Since the incident he has been acting a little nervous and jumpy. He keeps trying to find a place to hide, but I closed off most of the rooms because I'm afraid he's going to pee on stuff. He's been meowing softly off and on (which he usually does when he's stressed) but it doesn't sound like he's in pain. He and his brother have been fighting more than usually lately, which I've been trying to deal with. Also, my fiancé told me he was going to clean the littler box a couple days ago, but when I looked today it was pretty full. I don't in any way think this was him trying to mark his territory, there was just way too much pee. I'm also unsure as to whether or not he has a bladder infection. My other cat had one several months ago, so I kind of know what it looks like. I know I should just take him to the vets, but I'm not convinced that he is sick. I would take him in a heartbeat if I thought he was. Any advice would be much appreciated.

Hey,

 first off I'd suggest getting a second litter tray, and making sure that both are clean. Cats are fussy, the general rule is (number of cats) + 1 = Litterboxes you need.

I'm not sure which litter you're using, but cats can be a bit fussy with litter. The best thing to do would be to buy a couple of spare trays and fill them with different litters, clay, clumping, wood etc. Keep a close eye on the one your kitty is usiing and then introduce that slowly as the only litter before removing the extra trays. It sometimes isn't practical to have 4/5 trays, but it would only be for a short time. 

As you mentioned a UTI could be to blame, If this episode is very much out of the ordinary, and your cat is neutered, I'd highly suggest a vet visit. Or perhaps a phone call just to discuss the behaviour. A cat that is off food and drinking more than normal could be a UTI.

Can I reccomend soaking your sheets over night in lemon juice or white vinegar before a wash. Use a white vinegar solution on your mattress and use salt or bicarb crystals on your mattress before letting the cat have access to that area again.

 EDIT: I should have made it more clear that if they get their toilet scent on something they will likely use it again.

The skittishness and the fact that he peed so much and on himself sounds like a medical issue not territorial marking. I'd take home to the vet and get a urine culture and x-ray of his bladder. Something's going on.