Gaining..now what?

I had my surgery 5 years ago. I never reached my goal of 150, but I did lose 135 pounds, and weighed 200, give or take 5 pounds. Over the last 2 years I have gained back over 70 pounds, even though I haven't changed how I eat and I still exercise by walking and swimming every week.
My surgeon has retired and my family doctor is no help. He has tried to keep up with my labs and helped me with vitamins. 
When I had my BPD/DS, I was told that there is usually some weight gain over the years since our bodies try to recover from the original surgery, but I didn't think it would be this much.
I wonder what kind of revision I could get? Any Ideas?

Hello and I'm not sure if this will work but I've heard nothing but great things about it.  Check out the following link:

http://www.5daypouchtest.com/index.html I am going on 4 years out this year and have started gaining back some pounds (20) and I don't like it, so at this point I'm willing to give it a try.  I wish you the best of luck. Ms. Praise