What do you think this could be and treatment i could do other than what im doing now. (medical)?

Ok so about 3 years now I have been going to the cancer center for iron by IV treatments amd b12 shots. I have had 3 iron by Iv treatments. The 1st 1 I had lasted 12 months the 2nd 1 lasted 9 months and I had the last 1 in august of 2010. I was taking a b12 shot once a month now I take them twice a month. The drs have told me I will do this for the rest of my life. It seems like my condition is only getting worse. I really want to get better and the drs don't really know why I have these problems except my body don't absorb the vitamins and take them to my bloodstream so I have to get the vitamins in the bloodstream. I also have a problem called insulin resistance but its been ok for 2 years now. Any help or advice... I really need it. Thanks