Latest weight

Had my weigh in today with the nutritionist and things are still going steady. They use one of the scales that uses electrical currents to gauge your fat/non-fat percentages and it showed I lost 3/4 muscle to 1/4 fat. I am doing 30 minutes of cardio a day so I hoped that my muscle mass would at least hold steady. I am happy at the continued weight loss, but bummed at the mix. I know I must stay the course, but why am I so fixated on the bad news (muscle vs fat loss) rather than the good (20 lb loss in 5 weeks!!!)????