Hang in there. I would wait a few more days, then test again. Sometimes the HCG levels take time to rise. I know it is frustrating. I have been there before. Good luck!
Just wait and test again! Sometimes we test too early and don't have enough HCG in our systems, other times we aren't pregnant and our period is just off. I had a 49 day cycle one time and thought I was pregnant and couldn't understand why I kept getting negative results. It turned out I was not pregnant at the time. Good luck and hope everything turns out okay!