TMI Brown discharge in between period

Me and my boyfriend had sex the day my period ended. We used a condom, he pulled out before he cummed, and I am on the pill. The next day I was spotting brown discharge. Now I am supposed to get my period on next Tuesday and I am still spotting . (I also missed 2 pills)

I’m just wondering why I am spotting this brown discharge? Is it because we had sex the day after my period? Or because I missed 2 pills? It wouldn’t be pregnancy right? Because we used a condom, he pulled out and I’m on bc.

The pic is from today