what happened ??? did i gain weight over night?

Why are you even weighing yourself at night? Don't you know that the food and drinks you consume during the day makes you appear heavier? You might as well step on the scale with plates of food and cups of water in your hands if you're going to do that. And you messed up again by eating this morning before you weighed yourself. Weigh yourself first thing in the morning before eating anything, completely naked. That's going to be your most accurate weight. When you weighed yourself this morning, you may have needed to calibrate the scale first. This is basically resetting the scale so it will give you an accurate reading. To calibrate, step on it while holding something heavy, like a gallon jug of water and wait for the reading. After that, you can then weigh yourself for real and get an accurate reading, but only first thing in the morning. And if you're a female, don't forget we can retain water like it's nobody's business.

Could be water weight. If you were a little dehydrated yesteryear then rehydrated you could have put water weight back on.

Did you use your scale in the same place? It could weigh differently if you move it even a few inches especially in older homes where the floor is slightly uneven. That happens with my scale all the time

You're just holding onto water weight. Stop weighing yourself everyday. It'll drive you crazy.

Hello,

Sounds like water weight, this happens when you eat more sodium than usual or your period is due soon.

Probably had too much salt or carbs