Welcome to HCM,
Thanks for your query, since all the urine tests done by you are negative there is very low chance that you are pregnant. Doubt arises because you are not having your regular menses though you have signs of them. In this situation i would suggest you to undergo a whole abdomen Ultrasound
, if will serve dual purpose , will rule out pregnancy
as well will help search for the cause of your crampy abdominal pain
. DO take care of yourself.