Experiencing numerous days of dark brown dischareg

I went to my doctors office yesterday. I had my OB intake February 15th and a few days later they called to tell me I had a UTI. I finished the antibiotics like I was supposed to but a week ago I started spotting after sex. Haven’t had sex since then but the spotting changed to dark brown discharge and has yet to go away. Yesterday they said my urine showed no infection and did a pelvic exam swab to send to the lab. Now I am just waiting to hear back. I have yet to have an ultrasound. I have one scheduled for next Wednesday and this was a surprise pregnancy. We thought we were done but god had other plans. I’m very anxious and hoping there’s nothing wrong. Anyone else experienced the same issue?