Doggystyle & condom pregnant?

Odalys
Hello , my names odalys 
well my boyfriend and i had protected sex a month ago and i missed my period it was supposed to come on the 16th but im not quite sure since im kinda irregular. Well we tried doggystyle for the first time with a condom on him. Im wondering if by any chance i can be pregnant. Ive gotton the stomach flu a while ago is that why my period hasnt came yet?? someone please help me i need answers im really worried ):