Welcome to this site and I am sorry to hear about the problems you are having. The fatigue and anemia problems may be related. Although I have anemia, it has not been significant enough to cause fatigue. Other nutritional deficiencies might also be involved. My GP monitors my iron and ferritin levels routinely and the iron tablets I take daily with Vitamin C keep me in the “normal” range. If iron tablets do not do the job, your doctor can give periodic iron injections. You may want to look at the posts of others on this forum for suggestions that might reduce the problems you are having without having surgery, such as diet changes and measures to reduce rectal pain. Another thought is to consult with other doctors who are experienced in dealing with j-pouch problems. Cleveland Clinic had a very good record in this regard. If further attempts do not produce satisfactory results and going to an ileostomy is imminent, you may want to consider a procedure like the Koch pouch or BCIR that avoid having an external bag. I wish you the best!
Bill