Ah. My bad nerdo.   

Anyway, Are you getting enough exercise? Often, people suffer from muscle fatigue when they're not getting enough rest after exercising etc. Potassium and Magnesium are two other elements that you need to include in your diet. Also, are you eating enough carbs? You need carbs to keep you energized. When it comes to carb, look for complex carbs - whole wheat, legumes are some great sources of complex carbs. 

And again, maybe, just maybe, it is due to dehydration. If I were you, I'd start by drinking 8-10 glasses of water for a change.