There are a few checks that can be done. The BP that drops rapidly when standing can be a diagnostic. I love my Florinef! I reduced recently as I thought it may help the weight gain I have and today have been so giddy that I am almost falling over everytime I move- so have gone back to normal tablet now!! Its magic ( if you need it). I was not underweight when dx - by the time you get to that stage you are a stretcher case and near crisis/death. I think having MG makes us less active and gain weight ... and I also have low thyroid. But shades of grey re the adrenal symptoms- its not always black and white. Just be on the lookout. Hope you feel better soon.