Scale frustration

My scale is without batteries for quite some time now. When I started dieting and doing sports again, I first did it only for feeling better, I didn't intend to weigh myself at all.
But then i thought, fuck it, why should i relinquish the achievement of a visible weight loss in numbers? I didn't intend to overstate the numbers on the scale. Muscles weigh more than fat anyway, and i surely want at least some nice baby muscles. But I decided to weigh myself again, which I didn't do since months.
So with my broken scale, when I visited my doctor last Wednesday, I went on his scale instead. 108,3 kg. That's something I can work with.

Today I wasn't able to resist anymore. I was a good girl for over a week, dieting properly, doing my sports, I even already felt lighter than before. I wanted my scale achievement!
So I went to my pharmacy because I knew they have a scale. I took off shoes, jacket, scarf, and climbed the scale - and it showed 112,2. A hundret and twelve point two kg! I had a calorie deficit of over 500 each day last week, it's absolutely impossible that i gained three kg within 5 days. No fucking way!

Yeah, different scales give different results. In other words, I have no way to track my weight loss process over the last week, and I won't be able to do so until I get new batteries for my own scale. That's definately frustrating. Aaargh.