Definitely, the more you burn the more you will loose weight. If you want to maintain your muscle mass in the process you must give time for your muscles to recover. Do you wear a heart rate watch? If you are over training you will notice that your heart beat does not get up as easily as it used to get. Your body temperature will also slightly rise.

If you want to maintain your muscle mass it is necessary to learn to count calories. You should mark down everything you eat and make sure you take in at least 2 grams of protein per every kg you weigh. You also should not have a calorie deficit larger than 500 calories per day.