I barely eat, I get whiplashes then dizzy

I never done these ask this things before so yeah. I'm so tripped out, like is it like possible to get pregnant to get pregnant by anal? See me and my boyfriend never did anal, until I wanted to I'm was a anal virgin until this one night on jan2nd, we were tango-ing. He always pulled out and I never got pregnant until he said he wanted to cum in me while trying anal, so I let him and we did it, he only put the head in and then yeah he cummed, and I felt wetness. And he said to me not to move and close my legs when he got off cause we were in doggy style position, so I did close my legs as soon as he got off but seem like that made the cum slide.. not sure, he told me to wipe myself with a Kleenex so I did.. then I got in the shower as soon as he got off : Since then I barely eat, I get whiplashes then dizzy.. I know I have to wait until I get my period but idont feel like waiting I'm stressing myself out every damn minute. I'm expecting my period on the 14 of January,