is good for you
and will help build muscle, but you
have to keep up the exercise, too.
Not eating butter or cheese, doesn't mean your eating habits are excellent. You need to eat lots of fruits and veggies, along with high protein, lean meats, etc.
You build stamina by working into an exercise routine, slowly. Have you thought about trying yoga, along with other exercise? Yoga concentrates on relaxation, stretching, breathing, etc and go a long way toward building stamina.