Fludocortisone mainly controls your mineral levels and therefore your water retention and blood pressure. You would see a big change in your weight during the day if your fludocortisone is too high. Your weight would be lower first thing in the morning when your medicine levels in your blood stream are low. You weight will be higher in the evening if your dose of fludocortisone is too high because you are retaining water (assuming you are taking your fludocortisone in the mornings as most people do). I varied ten pounds a day and my feet were puffy when I was taking too much fludocortisone.
Cortisone controls your metabolism. Most people gain weight when they begin taking cortisone. I did. A few pounds is expected, but gaining 15 pounds in one year may indicate that you are taking too much cortisone and may need to slowly cut back. Also, look and see if your face is getting a round look and your face has a pinkish, puffy look.
Your doctor can test your levels and advise you how much and how quickly to cut back. Usually, cortisone is only cut a few grams every couple of weeks. This gives your body time to adjust. If you cut quickly, you can go into an Addison's crisis which is something you don't want to do!
See under my topics - medication