“I have abdominal pain and bleeding?”

I have never had any medical issues, except I had my period for a whole month back to back and then I got put on birth control. That was a few years ago. A week ago I started bleeding but it was not my period. I’ve been bleeding so far for 10 days And my actual period only lasts about four days. Soon after the bleeding started I had the worst abdominal pain I’ve ever had. I went to the ER and they said I have a bladder infection they only checked my pee. I did not get an ultrasound. It does not hurt to pee, I don’t have the urge to pee, my pee is normal. But the bladder infection does not explain the bleeding. What else could it be?