Yeah i got a colonoscopy about 3 weeks ago and i still have severe diarrhea is that normal or should i be concerned they cut a pre-cancerous polyp out?

No concern: medication taken to clean bowel could lead to diarrhea but having removed or not removed polyp, unless latter was malignant is unassociated with bowel malignancy. Unless congenital polyposis with APC gene mutations present, polyps only associated with 5% of bowel carcinomas. Latter derived from field effect, transformation possibly related to infection from organisms like polyoma virus