Could be girlfriend be pregnant??

Me and my girlfriend have not had actual sex yet but we have done other similar acts (dry humping, touched each other's genitals, etc). Yesterday, we did the same thing, she kept her panties on however I didn't have my underwear on. We decided to play and she got on top of me and "pretended" to have sex, I've read some articles that explain that the fluid that is created when an erection occurs has the possibility of containing sperm..and although pregnancy could occur, the chances are low. My only concern is that I "came" during the act but was able to cover myself with a towel...I didn't want to keep going so I stopped for like 15 minutes then continued. I took off my underwear again, and we did it again. Is there a possibility that she could be pregnant even though no intercourse occur??