Add electrolytes to your routine. That kind of fatigue is often a sign of some kind of deficiency. I recommend adding at least 2g iodized salt to your diet, and then something like a banana for potassium (or a salt substitute like NoSalt), and a Magnesium Glycinate (at night will make you sleepy) or Magnesium Citrate (might give you the runs) supplement. Or you can just eat magnesium rich foods, like spinach.
Since you’re not fasting more than 24 hours, I think it’s probably better to just try to change the foods you’re eating to include more of those electrolytes (salt, magnesium, potassium) rather than doing supplements, but if that’s too much trouble or you just don’t want to, supplements could help a lot.