Your muscle mass is dropping because your not eating. Muscle is active tissue, therefore takes energy/calories to maintain. When you starve that tissue, your body breaks down your muscles for fuel. You need to figure out an actual diet. Yah if your only goal is to lose weight keep doing what your doing, but if you want to lose fat and at least MAINTAIN a decent amount of your muscle, you have a lot of research to do. Go to the nutrition forum on this site. That's where you really need to be, supplements are the least of your concern right now.