Is it possible for the sperm to get through our pants?

I was at my boyfriends house, and we were both fully clothed. neither of us want to have sex, because of the challenges with that, and because we are too young for a child. So instead, we just fooled around in clothes. I was sitting on top of him, face to face, with my legs on either side of him. I was moving slowly back and forth because he said it felt good. He told me to stop a couple of times because he said he was going to come. So i stopped. And then he said to start again. So i did. after i got off of him, i saw that all of his jeans were wet, and he didnt notice. I told him, and he changed. Then he asked me to go check if mine were. So i did. And the crotch was wet. (i was wearing thin jean shorts) I said it was probably just wet from me. But im still sort of scared. Is it possible for the sperm to get through our pants and my underwear? Could I be pregnant? And how soon should i be expecting symptoms if i am?