Haven't had a bowel movement in over 3 weeks? My doctor says it's completely normal? Is that true?

I already have severe abdominal pain 24/7 (possible crohn's) and now I'm super miserable! My doctor doesn't think it's serious and won't take any drastic measures (misdiagnosed with eating disorder) and my parents agree?! What should I do? High amounts of fiber, water, dried fruit, ect., stool softeners, miralax, laxatives, suppositories, and enema's haven't worked. Magnesium citrate given at a colonoscopy dose have worked in the past but they refuse to do that. Is this something serious or could it cause complications?