scared!!

so last night i had sex with my boyfriend (unprotected) i don't think he came inside me cause he pulled out and i had to give him head for a bit before he actually came. but this morning when i got up a watery white kinda stuff ran down my leg! what could this be?
 i'm kinda nervous as i'm 17 and definitely do not want a baby right now. my period was due to start today, am i still able to get pregnant?