Osval,
I had the same thing happen to me at my last colonoscopy. The Doctor asked me how I was feeling before I went in and of course I said great. Normal Bm's, no blood, no mucus, no urgency I said to him that I was in remission. Then they did the scope and it showed active disease throughout, I was so confused as well because I seriously thought I was in remission.
He as well wanted to take the next step and try Imuran, and I said NO WAY not yet. If I was having symptoms and not able to go about my day normally I might have considered it but I asked him if we could wait it out. He agreed so I started my enemas and continued with my normal meds and I still feel fine. I will have to wait again until next scope.
In the past my symptoms were so bad when flaring, it was so strange to feel so good but inside says another story.
I told him that maybe my colon looks so active because of all the prep before the scope, its irritating, it has caused me to bleed in the past and I find it takes a good week or so for things to go back to normal after drinking and flushing out the colon.
If I were you I would listen to your body and not jump the gun yet.