gained weight scared!

it has been 7 years after losing 145lbs.  i did great till about 1 and a half years ago.  Weight started creeping up and now I am up 40 lbs.  I have  arthritis really bad in my knees and ankles so excersize  is out and i feel mersible never thought i would have a problem i was doing so well.  Any suggestions?  Have many of u picked up weight.  Going to doc tomm. I will discuss it with him.