What do I do now? More testing or go to my doctor?

I am three days late for my period which was due 2nd May, 2009. I took three hpts so far and all are negative. Today is 5th May, 2009 and Aunt Flo did not show this morning. Yesterday I had backaches, sticking pain in my , twinges in my left side and was very gy. However I have no symptoms today. What do i do now?