You have blood when you urinate? That's never a good sign and reason to go the doctor if you are saying this. You may have inadvertently gotten fecal matter in your urethra causing an infection (besides abrasions from rough sex) and have a uti. Antibiotics are required for that. But if you have blood I urine, that's usually involving the kidneys or urethra and you need to have a doctor culture it. good luck