Unless you ate 35,000 extra calories and basically sat in a chair all weekend, there's no way you physically gained 10 lbs. That's the good news.
It's probably all sodium. When you go from a clean diet with lots of nutrition (read: veggies) and minimal processed foods, going off plan for 2 days can throw off your balance. I'm sure the majority, if not all, is water weight but it can take a few days for your body to flush it out.
Don't get discouraged! Keep chugging and that weight will fly off, you'll see.