I have been having cramping and lower back and stomach aches for 5-6 days now. i've missed my monthly cycle by a few days, which worries me; but was told that it may be my gall bladder that was an issue (causing the pain). any insight would be nice.

Primary doctor first: A person with such symptoms can see her primary care doctor first (Internal Medicine or Family Medicine). The primary care doctor can do a general examination to see what might be the symptoms and the cause. Sometimes the symptoms are menstrual, but other times they are gastrointestinal. A urine pregnancy test is usually done for any woman of childbearing age, just to be thorough.