When u have c. Diff does your WBC count change? Why does it make you tired and weak, no energy

May or may not. Depends upon the extent of the infection. Your fatigue can have numerous causes, including electrolyte imbalance, severe infection, and so on and so on. You need to discuss with the doctor treating you. Good luck.
C Diff colitis is... Is an overgrowth of a normally well tolerated bacteria that is found in the normal intestinal flora. Its emergence correlates with repeated courses of broad spectrum antibiotics and is particularly problematic in immune compromised patients (eg., cancer patients). Wbc counts can be elevated, but not always, and patients may have both focal (cramps abdominal pain) and constitutional symptoms.