my period is due any day now. and about 10 days ago me and my boyfriend were fooling around, and he put his penis in me only for about 15 seconds. i know there is sperm in pre cum and thats why im scared. is there a big chance i could be pregnant from that? he's not very worried.. but i am. i havent been getting as many signs for my period as i usually do.. and i should be getting it in the next 2 days. im just worried, but since it was only for about 15 seconds i dont know if theres a big chance. please help!