Fat Gained 7lbs over 3 weeks. Eaten same cals and food drank same amount water and done same exercise and don't have periods. Ideas why?

You need to know how many calories you are consuming. A normal weight woman needs about 2000 (2500 for a man) Calories per day to maintain normal weight. Be careful to count accurately or it's useless. 1 lb of fat = 3500 Calories. If you eliminate 500 Calories per day from your normal food intake, you can lose 1 lb. each week (500*7 =3500). I've seen some people exercise, but they don't do much. They put little effort into it. They're not burning many calories. I burn about 100 Calories per mile walked, so I have to walk 35 miles to burn 1 lb of fat.

How much salt are you eating? Some of it could be water-retention. Even "good" restaurant-food is often loaded with sodium.

I doubt you've gained that much muscle in just 3 weeks...but maybe.