Have you had her checked for physical issues, such as anemia? It doesn't sound to me like the pitching routine should be draining her that much. I'd make sure there isn't something going on internally that the pitching is just helping to surface.
If you want to have a pitcher at the age of 14 and a relationship, stop what you are doing immediately.
Are you kidding? There is no excuse for overusing a pitcher at 7. Playing outside is far different than structured lessons and worrying whether a 7 year old hits her spots. Reduce the lessons, reduce the playing. There are years and years in the future for this kind of adult-supervised structure.
Do we let kids eat all they want? Miss school when they want? This is not about what a kid wants. It is about adults having common sense and limits. The PC should not be enabling this either.
1. Increase carbs the night before..... Spaghetti dinners are the fav in our house
2. Make sure she's getting enough water - electrolyte water helps to. We don't do Gatorade.
3. More sleep
If this doesn't help, then check your catcher. We just experience similar situation about missing spots and thought it fatigue but in fact it was the catcher not "working" as hard. Don't get me wrong....DD is NOT 100% accurate but we did notice a marked difference in the last several games.