Curious

Me and bf of 1.5 years have sex every few days. September 1, we were having sex and he hit the wrong spot and jabbed it kinda. It hurt him for a second and was back at it. At the end when he came there was blood kinda mixed in. Afterwards we checked me and no blood was coming from anywhere and there was none from him , he peed after and there was no blood. My period is also 1 day late and I've been cramping. Is there anyway it could have been implantation bleeding from a time before that night? There was very little blood. Neither of us bled after that or before that.

Also he came on my stomach