No sex but could still be pregnant?

My boyfriend and I have decided not to have sex because of how paranoid I get about getting pregnant. This weekend things heated up and we undressed and his penis was rubbing on my clit bare. It wasn't for very long, and he didn't cum. I was also on the first day of my period, and was wearing a tampon. 
I don't know if there was any precum. It was rather dry- which is why we stopped, so I personally don't feel like there was any precum. 
I cleaned myself off immediately after and changed my tampon. 
He had just gotten out of the shower, so I don't think it would be possible that there would be any dried cum residue on his penis. 

Glow Resources

Let’s Glow

Glow is here for you on your path to pregnancy

Glow helps you navigate your fertility journey with smart tools, personalized insights, and guidance from medical experts who understand what matters most.

25+ million

Users

4.8 stars

200k+ app ratings

20+

Medical advisors