First of all, let me answer your question. YES! I've had weeks like that. In fact, I just dealt with a couple in November so I know where you're coming from! I didn't really have a plateau (I myself won't be calling anything a plateau unless it's more than 3 weeks) but I had two small "stalls" where I ended up weighing the same two weeks in a row. It was frustrating to know I was doing what's right and there my weight was... the same as if I'd done "nothing at all". (How could I ever make my goals? I'm such a "failure" for two weeks the same... ; ;, etc etc etc....)
A day after my second "stall" I decided I needed to choose. Either I continue to wallow in my self-pity or I simply enjoy the changes that I've made so far. I took some time to look back over the past months of my weight loss. Mostly down, a few very tiny ups. But I kept going regardless back then... why should now be any different?
Now, this is your very first stall. You made it through & you lost the following week! You kept going even though I'm sure last week was a little discouraging. So why should now be any different? Sure it might feel
as though all your hard work was for naught... but really and truly, would you rather be 85+ lbs heavier right this very moment just because you didn't lose quite as much as you wanted? I doubt that.
It may also mean that you won't make a time-line goal... but maybe you need to reaccess that goal then. Goals aren't supposed to be discouraging. They're supposed to be something to work for! And if you don't make it quite this time, then gosh darnit you're going to get as close as possible! And next time you'll make a plan that isn't necessarily "timed" so that you can enjoy the next 10 lbs you lose regardless of how long it takes you to lose them!!!
An 85 lb weight loss is AMAZING no matter how long it takes to get it off ^^ So pat yourself on the back, and accept that there will be weeks when you don't lose what you'd like.
Stop focusing on what you would've liked, and start focusing on what you've got or in this case lost.