ok could say so many cliche things back to this like ,,,if he really likes you he wont really care how much you weigh,,,or you should only be losin the weight for yourself not for him.
But ive been there myself,,my advice get on SS keep reminding yourself the real reasons you want to loose the weight, and by the time your date comes if you have got back to your original weight or not you will feel great as you wont be the weight you are now!!