Am I??

I havent had my period in 51 days and counting. I've been stressing loads about it but I dont normally so that probably doesnt help. This may sound really dumb, but I wanked off my bf and he got cum on his hands, so he went off else where to change or something. When he came back, he half fingered me. Is there any chance I could be pregnant or and I just worrying about nothing?!!