Good luck for your weigh in, GI!
Hopefully you'll have a loss, but if you have a little gain, just put it behind you and get back into your healthy habbits ASAP
Don't let a gain derail your efforts, you've done so well to lose 6kgs already!
It might sound silly, but if I have a loss one week, and a gain the following week, I sometimes average them out. So if I lost 6kgs and then gained back 1kg, I'd think 'well, I've still lost 5kgs in 2 weeks - a loss of 2.5kgs on average each week'. I find that it helps to keep me in a positive frame of mind, and considering that on average a 0.5-1kg loss a week is healthy, it helps you feel like you're still on track too.
All the best!