My last day on my period was may2 and since then I haven't got my period what can be wrong.

Dear Anon, thank you for writing. Are you 100% sure about your dates? Assuming that you are regular, I would suggest seeing the doctor for a blood test to determine if in fact you are pregnant. If not, he or she may be able to help you pinpoint the problem--if any. At times, although not so common, the pregnancy test may not pick up the hcg levels in your urine therefore giving you a negative. Or, the test may have been performed incorrectly. Either way, after 3 weeks if you have not gotten your period (and you are normally regular) then that is reason to see your doctor. Goo Luck and please keep us posted!