I agree with Lisa. It's very disheartening to see fluctuations across the week and days, as I used to be the kind of person who weighed herself fifteen times a day because I so desperately needed the motivation - it simply wasn't coming from within at all, I had to have external factors pushing me on. That's probably why I'm successful at the diet now in comparison to all my abortive attempts, because the time it's really coming from a deep down desire to change. I go by my scales at home rather than my counsellor's (although thankfully the readings have matched thus far), but that's because I have to live with my scales. There's no point in my getting used to a reading on my counsellor's fancy set-up if it bears no relevance to the one item I have to monitor me post-diet! Whether you'll have dropped a couple of dress sizes by August is hard to predict, because it all depends on your current weight and natural frame etc. I'd heard that a stone loss equates to one dress size, and you ought to lose a stone within a month so you ought to be at least one dress size smaller. On the other hand, I have more than nine stone to lose but if I lost nine dress sizes I'd be down to about a 4/6 going by this theory, which is ridiculously untrue, so it varies for different people. Either way, regardless of how much or little weight you lose, you will be smaller and happier and regardless of how much or little weight you lose you can still go swimming with your son. He'd love that, and you can't get that time back so enjoy it and don't give a moment's thought as to your weight. When you put something as unimportant as weight against something as precious as family time, there can only be one winner.
Lisa, I'm two months in and I do the exact same thing! "By my holiday I should be..." "By Christmas I should be..." I use it to spur me on. I remember Christmas last year, all 23 stone of me sitting on the sofa and watching the Muppets' Christmas Carol in my frumpy jim-jams, and it's possible that Christmas this year I'll be a "mere slip of a person" at 13 stone (not exactly lightweight but hey, to an ex 23-stoner that feels positively waif-like), in potentially much nicer jim-jams but inevitably still watching the Muppets' Christmas Carol.
I have a million mini goals to get me through. I monitor myself in terms of stones, pounds, kilograms and BMI. Every time I break a barrier, e.g. my BMI drops a point, or I lose a kilo, or move into the next stone, or from having a weight in pounds that begins with 26X to one that starts 25X, that's something to celebrate. I treasure each and every milestone, because they're all my tiny little victories!