Urinary tract infections can cause hematuria (blood
in the urine). Other causes of blood
in the urine are urolithiasis (
bladder stones), kidney stones, bladder cancer, or kidney disease, bleeding disorders and others. It is best to take her the vet first thing tomorrow for a urinalysis, X-Ray of the abdomen, and complete blood work.
If she has bladder stones thay would have to be surgically removed.