I have been constipated for a while and can't remember last bm. Normally go once every 2-3 weeks. I feel and see bulges in abdomen. When to go to dr.?

Should have seen a. Doctor along time ago! 2-3 weeks between bowel movements is not normal besides making you crabby and miserable. See your doctor or get a referral to a GI doctor and be honest and discuss all your meds, diet, fluid intake and activity with them.
Yesterday ! The average bowel frequency in america varies from 3 movements daily to 1 every 3-4 days.You are clearly outside the bell curve & need help now. Whether you have colon inertia, rectal dyssynergia, partial obstruction (intrinsic or extrinsic), ischemic gut, metabolic "imbalance", or some other disorder you should get checked & treated. Age, co-morbidities, longevity of symptoms may alter prognosis.