Sounds like increased muscle mass to me, I'd be kind of surprised if it wasn't, with all of the exericise that you're doing.
I have some photos of me from 10 years ago, when I weighed 7lb less, but I was carrying significantly more body fat. The difference is that I now have massive runner's calves and thighs, that weigh significantly more than the body fat I've lost.
I don't think that 2 weeks is enough time to observe weight loss anyway, there are all sorts of natural fluctuations that could mask any legitimate weight loss.