Ectopic? Bleeding 11 days before period..

Ok so, my period has been very regular for the past year since having my second child. I am 11 days from my next period, so about CD 18 of a 28 day cycle. Tonight during sex I started bleeding a fair amount as if I was actually on my period. SO and I had unprotected sex 2 days before my last period and on my 3rd day of my period, each time after that was protected. Since the day after/2 days after my period ended I started getting dull period cramps but ONLY on my left side, and it would radiate to my left knee and my back(which is normal for my period pains but on each side and only while on my period).

At this current moment I still only have that dull period pain on my left, I’m still bleeding/spotting but only slightly. Does this sound like an ectopic pregnancy? Will it show on a pregnancy test either way? Why else would I randomly bleed like that during sex?

Sorry for all the questions this is a first for me!