What Causes Lower Abdominal Pain And Pink Vaginal Discharge Post Total Hysterectomy?

I had a total hysterectomy back in September 2014. Within the last 2 weeks I have been experiencing some abdominal pain on my lower left side. It is especially painful during sex. After having sex yesterday hours later I discovered that my panty liner was full of light pink blood. Also during surgery I had a complication where my colon was accidentally torn and had to be repaired right after. What could be causing this.