I suspect your problem is caused by your antidpressant as this is a side effect of many antidepressants.
Try docusate (Colace ), an emollient type of laxative better known as a stool softener. If your problem is infrequency, choose a bulk laxative such as Ciitrucel FiberCon, or Metamucil. If you have both complaints, take both kinds. Despite lore to the contrary, both types of laxatives are relatively safe for long-term use, but check with your physician.
Colectomy is used to treat and prevent diseases and conditions that affect the colon. I have not heard of a surgeon doing a colectomy to cure constipations after just 1 year. I would be very leary of a physician who would perform this surgery at your request without a known bowel problem such as cancer, Crohn's Disease, Bowel perforation, Bowel obstruction, Ulcerative Colitis etc.
Please do look into other ways to deal with your constipation and perhaps get the advice of a GI specialist.
I wish you the best,
Kitt