The advice given already is so true! Its not the end of the world, but I know how you feel, I too fell off the wagon tonight! I was doing so so well as well, I even exercised today.
I had eaten dinner early, so I was getting a pit hungry and couldnt resist the grapes and blueberry bagel with cream cheese calling my name. I was then 500cal over my daily limit! Aagh! I feel sick and horrible! Oh well. Tomorrow is a new day.
Good on you for losing 5 kilos though, that is fantastic! Think about it like that, you are doing so well already, its ok to have a small slip up, and at least you will be more aware for next time!
Good luck! 5 kilos is fantastic! I cant wait to start seeing changes in myself, early days yet though! I'll just have to be patient, lol.