Help!

My husband and I have been TTC for almost 2 years. For the past couple weeks I've been experiencing cramps and nausea in spurts throughout the day, especially after I eat. Meals are usually followed with some diarrhea or constipation. I'm over 1 week late for my period, have taken 2 tests and both were negative. No breast tenderness or soreness, but can't seem to fight off the fatigue. Am I just hoping its pregnancy, or is it possible I am and both tests just didn't work? What should I do??