I have missed my period..have my tubes tied, but doctor took pregnacy test it came back neg., had a pap smear @ blood work come back good.wat could it b?

If all the blood wor: Work is neg, could be from stress, or pelvic problems, u need an ultrasound to r/o cyst, etc., your doc needs to do an ultrasound on u, if all teh other hormone tests and us is normal, doc can give u meds to induce a period.

Hormonal imbalance: Menstrual irregularities are not uncommon and anovulatory cycle is a common cause. If you miss more than two periods it would be time to see your doctor. Consult this site. http://www.nichd.nih.gov/health/topics/menstruation/conditioninfo/Pages/causes.aspx