What Is The Treatment For Severe Cramps , Nausea And Vomiting During Menstruation?

hi,am 3 days late for my period and have been having bad period like cramps for roughly a week and a half,along with nausea vomiting excessivley tired,sore breasts,did a pregnancy test yesterday (first urine of the day)it was negative last lmp was 7/03/11,could i still be pregnant?