HELP! Am i pregnant?

So my boyfriend & I had unprotected sex 3times in a row. I wasn't fertile during that time but now it's been a month since it happened & I'm expecting my period today but for the past 2 weeks I've been cramps on my lower stomach & my lower back & now I'm really sensitive so smells that I used to love & i can't stand certain foods nor it smells because I feel nauseous. Ive been feeling dizzy & I've been having head aches. Is it too early to know if I am or I'm I just crazy?