And I'd also like to suggest that since you went from virtually no exercise to riding 6-10 miles daily - your body is adjusting. Are you sore at all? (I would be!). If so, then it's very, very likely that while your muscles adjust to new activity, they are retaining water.

You have not put on muscle in just 10 days. Even the most gifted weight lifters can't do that! And you've also barely given it enough time for any created calorie deficit to kick in. I think it's water weight.

Keep it up, enjoy riding for the FUN of it...and you will see results. It's too early to get frustrated!