How much did you drink? 10lbs in one week is almost certainly majority water weight.
Another thing to consider is how much do you weigh? 10lbs to a 300+ lbs person is a lot different to a 150lbs person.
Are you a female? Hormonal changes can have significant short-term effects on weight, especially around the time of a period.
Ultimately, should you be concerned? I wouldn’t be personally, a one-off 10lbs is likely water weight and will either go back on when eating normally or you’ll find you’ll struggle to lose weight for a few weeks while it all balances out.
However, you know your body best and if you feel concerned then it’s always best to speak to a healthcare professional rather than Reddit.