Precum and Pregnancy?

Im 19 years old and my boyfriend and I were fooling around yesterday and after a little while he began to rub his tip against my vagina but never entered. I know there was precum because I felt it on my hand. My question is: what is the possibility of me getting pregnant from this? I ALWAYS take precautions with this kind of stuff...but I ran out of birth control pills last month and I haven't had the money to get any more. Even though I have condoms all the time, I didn't plan on getting that far and as soon as I clicked into what he was doing I told him we had to stop, but he was there for about 10 seconds at least and was in direct contact. I also just finished my period a couple days ago. Since I have always been careful I have never been in this position, I've done some research but I haven't found conclusive answers either way, plus I need to know the possibility for this exact situation to satisfy my own concerns. I'm trying to stay calm but I have to admit, I'm freaking out a little bit. I'd like advice and opinions from others please!! Thanks in advance.