Urine

Yesterday me and my SO had sex and everything was fine. I went to sleep and when I woke up this morning and I had to go pee, so I went to the bathroom and i noticed that it was hurting me to pee and i went to wipe and there was blood on the toilet paper. It’s not like period blood it’s like a watery blood. If someone could help me out on what this might be, it would be really appreciated!