Don't worry your body does funny things.
Last 2 weeks I lost 2lbs which I was fine with and then my LLC kept saying "Are you disappointed, have you eatten" cheeky woman!
Then this week I lost 6lbs!!! So it was 2lbs, 2lbs, 6lbs, with no difference in packs/water or exercise.
2.2lbs is still a hell of a lot of weight.....like Claire says carry it around all day, or imagine what 2.2lbs of lard looks like, I'm sure you would rather that was off your body!!! :-D