We all have those ups and downs, unfortunately!! I recently had 2 or 3 weeks where the scale didn't budge an ounce!! Just about killed me, but I just had to keep in mind that it kicks back in after a while.
As people have said a million times, we didn't gain it overnight - we aren't going to lose it overnight. Of course, crap like that never really makes you feel any better when the scale is stuck! LOL
Good luck everyone, and just keep plugging along. We'll all get there someday!