A couple of months ago I was on antibiotics for a uti. After receiving my period a week late it was pretty heavy. Now I'm not supposed to get my period until the very end of this month. I had sex about three times around the time I was fertile but am pretty sure I'm not pregnant. However during this week for the past few days whenever I go pee after I wipe I'll have some brownish/bloody discharge. I'm not in any pain or anything but I'm wondering what might be causing this? I read online implantation bleeding occurs more closely to your period and takes about 6-10 days after fertilization and the day I first had sex was the 9th but he did not cum and the 10th when he did but not inside of me. It's now  the 20th which is 10 days later but this bloody discharge began a few days ago when I was on my week of ovulation. And like I said I doubt I am pregnant. I've read about spotting during ovulation but I've never had it before. Anyone have ideas on what could've going on?