What Causes Severe Constipation Post Haemorrhoidectomy?

hai doctor iam sai, 22 years,had hemoroaidectomy surgery in past 25 days back,now i cannot passing my stoll like a normal person,when i passing my stoll little blood are mixing with motion,and stool are passing with smaller width or size.iam using oxerute cd tab?and cremaffin syrop. i got scared and feeling nagative such i will be operated again.sir please advice me what to do,and can i use stool softner[miralax] with the above tab