PLEASE ANSWER could precum go through shorts and get me pregnant??

Patient: Ok so my boyfriend and I were dry humping. I was not wearing anything and he was wearing boxers and a pair of athletic shorts like basketball shorts. I was on top of him for like a minute or so and when I got off I noticed a wet spot on his shorts. His boxers had a couple of wet spots on them as well from his precum. I am wondering whether or not or how likely it is that the wet spot on his shorts is his precum that soaked through? Also is it likely that I could be pregnant if it was his precum? My period ended about a week ago which most likely means I am ovulating, does that make it any more likely? Should I get plan B?