Right then...
1) DO NOT GIVE UP
2) don't trust the accuracy of a computer game that relies on a board that gets hauled around the house. one inch out of place and it could say something different to normal.
3) Don't be scared of putting weight on, especially small gains like 1lb and 0.5lbs...gaining a bit back every now and again is part of weight loss journeys (we might not like it, but I'm sure everyone has had weeks where they have unexpectedly gained a little).
4) if you really have followed 100% it may be your bodys way of preparing for a big loss next week. Just keep at it 100%.
We will all get to where we want to be in the end, but we have to remember that our bodies do not only respond to the food we put into them. It's helps if we feed them well, but stress, anxiety, family and work problems and even the weather can affect all the biological and chemical processes that go on in there every day. And that is beyond our control. But we keep fighting it, and eventually we get ahead of it by a lb or two. But if you give up, you are letting the tummy gremlins win, and you'll feel worse for it in the long run.
Chin up...and onwards with the free food!