I cough up all colors! Sometimes clear, sometimes yellow, sometimes green! It's usually thin watery but sometimes a little thicker. I don't have MAC but I do have pseudomonas and have recently recovered from pseudomonas double pneumonia. I'm 77. I could barely walk because of shortness of breath for quite a while but I am walking now 18 minutes 1/2 up a hill now. I do take xanax before doctor appointments because they cause me panic attacks. I got scared when I had heart failure left ventricle but it has resolved itself and my heart is back to normal.. I had difficulty sleeping because of worrying. Cardiologist was going to implant a defibrillator if my heart did not improve but Thank God it did. I don't know how to help the worrying. It hits me at night and is like a hamster on a wheel but I try every day to "focus on what I can do not on what I can't do". Sometimes I take a xanax to sleep.