I haven't had bowel movement after rectocele surgery and taking several laxative. what could be wrong?

Consult your surgeon: You might have stool impaction, but this requires an urgent call to surgeon who performed the operation.

Depends : Depends on a host of issues - how long since your repair? Did you have a bowel prep? How much narcotic are you taking? Are you pushing hard? There are many questions. The point is, speak with your doc about this. This needs a conversation. More than likely this is constipation, and nothing else, but this needs a conversation.