Yep, I gain up to 10 lbs. As I lose weight, the number is dropping somewhat (when I started it wasn't very unusual to gain 12). Now it's usually down to 8.
I used to find it extremely frustrating until I really asked myself why I was letting something "normal" upset me as much as if I had done something wrong. I kept trying to find ways to outsmart my body, and I realized that during TOM, I must need that extra water for something, so I might as well accept it.
I still get a little twinge of annoyance, especially when I was a TOPS member in a group that charged a dime fine for every pound gained. All the dimes were then given to the biggest loser for the week. On one hand it wasn't fair (I thought) that I had to pay up to $1 in "fines" during TOM week - but it also wasn't fair to everyone else that I won the biggest loser prize the following week when I lost TOM weight (which usually more than paid for my previous week's fines).
I've also found that when I eat low-carb, my body holds on to more water. If I'm going to have an especially high-carb day (where I'm still counting calories, so I know it's not a "real" gain) I have to make the mental translation in my head that I'm going to see a temporary water gain until I return to my normal lower carb eating.
Taking the frustration out of the equation as much as possible helps me stay motivated. When I allow that anger/frustration "it's not fair" mentality, quitting becomes tempting. And quitting is the only thing I've vowed "**** or highwater" not to do.
The group I belong to now doesn't charge for gains at all. Lose or gain, everyone puts in a dime, and the biggest loser wins all the dimes.