Dry humping and pregnancy

[Anm45]

My boyfriend and I started to dry hump a few days ago. I was a wearing bathing suit bottom with a dress. He was wearing what looked to be basketball shorts. He started to move on top of me and I felt him go inside just a little bit in the bathing suit bottom, but never fully penetrating. And then he would move out and would start moving against the side of it. And again sometimes he would go near my vagina. I was wearing a panty liner too because I was supposed to get my period that day, but I think it only covered the top of myself. I keep track of my period on an app because it's not completely regulated. Sometimes it happens a few days early or a few days late. I'm two days late which is usually not a problem, but considering he ejaculated on me worries me. I've read online that there's small chances of pregnancy due to dry humping, even while being a virgin. Knowing my luck, I've been scared since.
I would like some advice on the issue from professional opinions.