I Already Have A J-pouch From Surgery I Had In

I already have a j-pouch from surgery I had in 2010. My doctor said that my iron level has dropped quite a bit and thinks I have a slow bleed somewhere. He thinks it could be in the pouch. He is giving me a month of taking iron to see if I can get my levels up. After that if it does not rise he wants to do a scope. i do terrible with anesthesia and am sick for several days after. What should I be looking for and how do they fix the problem if that is what it is?