What Causes Blood In Urine While On Antibiotics?

I am wipeing blood after I urinate, I went to the doctor they test my urine ,no blood urine,but something was kinda high,with the urine,but Ialso had a sinus iinfection, I was antibiotics to take for ten days 875mg pen/amox.since ive been taking the antibiotics seems like it has gotten heavier., also I am 54 and ha a partial hysterectomy.