HELP, I MIGHT BE PREGNANT

My boyfriend and I have just started being intimate, though we haven't technically had intercourse, He'd rub my p__s in and around only the opening of my va___a. He have been extremely careful with me and haven't ever ejaculated on or near my va___a, so He wasnt really worried about anything, but bow i am worrying about being pregnant from his pre-c_m, and he’s starting to worry too. My period is late 2 days. Technically i am still a virgin because my hymen is still intact ("cherry" has not been "popped"). I know that even if having penetrative s_x, the chances of becoming pregnant from pre-c_m are low since there is a very minimal amount of sperm in it, so my question would be, "What would the chances be of me becoming pregnant by pre-c_m knowing that we've never had penetrative s_x and also that i am still a virgin?"