Need helpful advice

Elizabeth • Mommy to two beautiful baby boys
Okay so my period is about two weeks late, I've taken two tests and they were both negative, I had sex when I was ovulating on February 23rd, and had my period shortly before that around the 12th of February, I've been waking up feeling nauseous, I haven't really been able to eat, I feel sick, my pants are barely fitting, I have really bad heart burn, I've had cravings for pizza and funyuns like crazy, and really bad back pain and lower abdominal cramps, I just figured I was going to be starting my period but I still haven't. I'm not sure if I'm just crazy or if I could be actually pregnant. Please give me some advice. Comments would be greatly helpful