It happens. The first 4 days starting back, I lost 3, gained 5, got stuck there for 2 days, skipped a day weighing, and yesterday had a 10lb loss. O.O I though something was wrong with my scale. XD lol. But it was my Body being weird and hormonal is my guess.
Did you look at your sodium intake. Sometimes we consume too much of the stuff and our bodies hold on to extra water. Calories and everything else will be bang on with your dieting plans, but the salt causes a weight increase.
Either way I'm sure those extra pounds will slide off in the next couple days. :D
You can do it!!