Sorry Liz, I feel your pain...literally! I have the same problem only worse I think. I have a 25 Lb. weight limit. It sucks makes it hard to lose weight, ect.
I have good days and horrible days and I just have to accept it. I wish you the best of luck. Man do we have to have this in common too??!!

25lbs? I could just still pick up sam cat!

Wow that's a big cat,lol. It was especially hard when my kid was an infant, carrying her around all day and when she got close to my weight limit, I was suffering all the time. I have to divvy up all my chores, for example I can cut the grass one day vaccum the other. We have a big yard. But otherwise my back will go out and that could be for a week if I am not careful. There are a lot of peeps that have it worse, or so I keep telling myself,lol.

Yeah, Sam's around 21 - 22. Its hard keeping him on a diet, when I have 2 other cats who are skinny minnies.