10 lbs. sounds kind of low for 8 weeks after starting out, but everyone is different and 10 lbs. lost is 10 lbs. lost. Had you cut out most sugar, starches and grains in that time? Eating plenty of protein? If you were swimming a lot you might have gained a decent amount of muscle mass as well which can skew the scales a bit. When I originally started at the local CrossFit gym a few years ago I didn't lose a pound in the first three months or so, but my clothes were fitting better, my pants fit around my waist like I'd lost 20 and I was noticeably leaner. I had obviously kept up pound for pound in muscle gain with the fat loss. It's one of the reasons that I take how I look physically and how my clothes are fitting as more important than the number on the scale. Scales don't measure fat loss which is the goal. Not just weight loss.

Point is, if things are going in the direction you want, but not necessarily the speed you expected, it could either be that you just can't lose any faster, or we need to tweak things a bit. That's the thing about diet and exercise; you need to find what works and tweak and experiment with things to improve it further.