Implantation or breakthrough bleeding?

I got spotting 2 days ago, this was extremely weird for me as i never get it. I’m really good with my pill I always take it, but during my previous period I was on an antibiotic, macrodantin for a UTI. I heard antibiotics can mess with the effectiveness of the pill but not all, my doctor never specified and surely she would if it was to mess with it? I had unprotected sex using the pull out method on Saturday which was 4 days ago (keep in mind I’m

Still on the pill). I read that implantation bleeding occurs 6-10 days after conception. Am I just being paranoid or what should I do?