If you missed your period and if you are regular on your periods, you may take a blood test
as your urine tests have not shown up anything. Your symptoms could be either due to an early pregnancy or premenstrual and need to be aided by confirmation; a trans-vaginal sonogram is advisable if you have missed your period for more than a week. Please do not take Ibuprofen
as it is not going to help with your pain and it is not advisable if you happen to be pregnant, instead you can use one of the anti-spasmodic medications. Please see a gynecologist for further advice. Take care.