Don't they? I had weighed myself this afternoon, and i weighed 175. Now we just got home from going out to eat and i was in my mom's room so i stepped on the scale and i weighed in at 182! That cannot be right can it? I didn't eat much. Just a normal burger. I can't have gained 7 pounds!
Don't forget, your weight fluctuates alot depending on alot of things. Believe it or not, even the clothes you wear will make a difference. If you wear shorts and a tshirt one day, then jeans another...jeans weigh a LOT from what I've heard. Plus, for us lucky women out there, just before or during our period some of us retain alot of water. Also, I'm not sure if you were saying you weighed yourself on two different scales, but that can make a difference sometimes too. If it's not a digital scale, make sure it reads at zero to start...mine seems to move around a bit sometimes. Plus, not sure if it's how even the floor is or what, but I've heard that you should keep the scale in the same spot too because that can make a difference. Not sure why really though.
Glad you're back where you were before. Nothing more depressing than thinking you gained so much so fast. Oh, and as the other person said, always weigh yourself at the same time...preferably first thing in the morning