hi there, kindly get a pregnancy
test done along with an abdominal ultrasound
. Sometimes implantation
bleeding may present in this way and mimic a normal menstural cycle. The cramp and vomitting could be explained if you were pregnant. The ultrasound will rule out any extrauterine pregnacy if preg test is positive. In such case do visit your doctor and get immediate attention. In the meanwhile you could use an antispasmodic to stop the cramp. Take light small meals and plenty of fluids. Take care.