Hi I'm 22 I have one 3 year old boy and I think I'm pregnant, my mens was on the first week of april and I had sex on april 10, since then I'm feeling extreme tiredness, headache, vomiting nausea, hightened smell, and food cravings, on my calculation my period should come today, but its not giving me any signs of having it, and I'm feeling some firmness on my lower abdomen.. Can I be pregnant?