What happened with my weight?

I'm sorry to say I don't have a straight answer but just ignore the dude above me he's just an advertiser. Maybe your jeans still fit because you didn't put on any weight there. Many peoples weight ends up in their stomach. If you are still very skinny maybe your fat just turned into muscle which I think is heavier than fat. Not sure though. Maybe you just misread the scale the first time you weighed yourself. Hope this helped!