pregnant??

A
I was having sex, he came right on my clit, and then I started rubbing my clit to get an orgasm. Could the sperm have seeped down into my vagina and done anything? Because I'm supposed to start my period and it hasn't come yet.
I usually know when I'm about to start at least a week ahead because I get redish-brown discharge five days before my start date, and also begin getting cramps two days before my start date. But I haven't received any of that.
I was supposed to start yesterday.