Yes, I definitely agree with Sue. At this stage post takedown, you are still recovering. You are not automatically "cured." It can take time. I definitely had very low energy after my colectomy, which lasted a number of months. I'm not sure how sick you were before your surgery, but I was quite ill and malnourished. After surgery, I experienced a number of symptoms including hair loss, at times debilitating fatigue, reduced appetite, depression/anxiety, frequently feeling cold, poor exercise tolerance, and inability to gain/maintain weight, among other things. While these symptoms can mimic other disorders, don't underestimate the effects of UC on your system. By all means, talk to your doctor and have blood work done to rule things out. Also, your symptoms may point to nutrient deficiencies secondary to the UC, which should be checked. In my case, I had low potassium and low iron which were secondary to the UC. I started feeling better after I began taking iron supplements and got my potassium levels normalized.
Also remember that everything else aside, you just had major surgery. It can take your body quite a while to recover from that!