Do you have your own scales at home? I have quite a good set, which are consistent even though they weigh 8lb over. I know this because I get my cousin to weigh herself before she comes on her practice scales (she works there) and then check mine. I work to the higher weight, though!
I find that by weighing once a week I can check my rate of loss (or not!). I'm not worried about my actual weight, (that doesn't bear thinking about :shock: ) just that I'm losing. So then if I do get on the scales at my practice and they differ greatly from mine, I can shrug it off because I'm sticking wih mine.
It does sound to me that the practice scales were wrong, unless you''ve gained a lot of muscle. You weren't carrying your handbag, were you? Happened to a friend of mine - her handbag weighed 10lb! :lol:
And of course there's fluid retention and time of the month - that used to do a good half-stone, with me.
It's worth keeping a note of your measurements, as well, once a month or so. They tell the truth.
It could be something as simple as writing down 9st 8 instead of 8st 9, or similar in kilograms. Human error!
Don't let it get you down - you know what's happening to your dress sizes etc.
Viv