Would implantation bleeding happen a week after sex?

I’m on the pill and I take it perfectly, exactly at 11 pm every night and I haven’t accidentally skipped one for a few months. However, I know that even with perfect use, the pill is only 99% effective.

Anyway, i had sex last Tuesday after taking my pill for the night, and he came in me. Last night and today, I’ve been noticing some pinkish blood when I go to the bathroom. Usually this only happens when I skip a pill but I haven’t recently. Is it possible that this could be implantation blood?

My period is supposed to be here October 26.