Well, when you weigh yourself, you should always:
- weight at the same time - prefferably morning before bfast.
- not wear anything or wear the same clothes
- don't pick that time of the month for weighing because then you add water pounds regardless
- use the same scale (don't weight with different ones, they can vary wildly)
Anyways, you can gain 7 kg of pure muscle, but maybe in like a couple of years, so it could be some new muscle, water weight, or you didn't go to the bathroom, or you just ate, or some added fat or a combination of all. Or you didn't weight yourself correctly the first time.
A much better way to realise how you look is measuring bust/waist/butt. Because when you lose weight, even if you gain muscle, muscle is more compact and smaller, and you'll be losing inches. Also should be done morning, before you can eat/get bloated/get swollen muscles from exercise/etc. Just remember to measure waist at your belly button (that way you don't end up making errors by measuring higher or lower, and getting different results) and measuring the fattest part of your butt (basically make the tightest measuring tape circle to be able to slide it from waist downwards without wiggling).
As for my efforts, well I didn't gain
, but then again I wasn't very strict, and had a few relapses. But I'm getting used to eating less, as a habit, and not as a "omg, conscious dieting with effort"