You have done urine pregnancy
test and has come out negative. But you have symptoms like pregnancy except stomach pain and cramping. You can still repeat same test on early morning sample as result might come positive after some time.
If still result comes out to be negative; then it could be just your pre-menstrual symptoms appearing like abdominal bloating
Need to rule out food poisoning
or acidity. Make sure you had no other different food causing above symptoms. But in that case you will experience lose motions also.