Bengal Cat Spraying Again? Blood?

I have a Six year old Male Bengal Named Chikotay, he's been fixed since he
was six months old. Over the past couple days I've been finding little
puddles of bloody urine on the ground. Now I have four other cats and two
small dogs. So it was tough to figure out who was leaving the puddle.
I easily eliminated the dogs, since they are potty trained in a box with
puppy pads instead of dog litter.
Today, three times already in about three hours time, I caught my Bengal,
walking upto the cabinet door in my kitchen and standing with his backside
to the door, tail going nuts like he was spraying. And each time he did
this, he would leave a Uriney smelling bloody spray on the cabinet door.
Any advice, my vet cant' get him in till atleast monday afternoon.
Is it possible for cats to be able to spray again even tho he's been fixed
for years.
I know that the blood could mean a variety of things, kidney stones, bladder
infection......
Any help is Greatly appreciated.