Weird situation

I’m currently 13 weeks pregnant and yes I did go to my Ob but they really couldn’t give me answers on why this is happening. Every time I go to the bathroom I am peeing small blood clots. When ever I wipe I’m not seeing anything. I am not spotting at all, and nothing on my panty liner which is really weird. I did a ultrasound and everything seemed normal but I’m confused why it’s still happening. I only see the blood when I pee. Any advice would help! I have never had this happen before💔