Young and maybe pregnant

I honestly get annoyed at all the young girls thinkin they are pregnant on here when there is no way they could be but I am very concerned. I am 16. I gave my boyfriend a handjob in a hot tub. I was sitting on his lap backwards so his penis was really close to me when he finished. I am on birth control but always forget to take it so it has like a 40% chance of being affective at this point. I forgot to take a pill about a weeke after we did this and ususally when I forget I have a period and this time I didn't. I have been very very hungry lately. I never even thought of the chances of me getting pregnant but now I'm worried