Mine was horrible this month also, but only 5 lbs for me.
I can imagine how horrible you feel with 10lbs-yucko!
I have vowed to not weigh during that week. It's just too depressing.
It sounds counter productive, but do you drink more water at this time also?
I know for me it's because I crave salty foods-chips, cheez-its, etc-that I retain more water, so I try to drink more water to flush all of the sodium out.
Best wishes