Much more likely a long series of infection agents can give chronic fatigue, many parasite organism living in human body, virus, bacteria, worms, flukes etc will steal energy, often because immune system continuously have to keep fighting it without winning....
wide testing for lots of microbes, parasites, viruses is necessary.
If nothing shows up some empirical treatment with some wide specter antiparasitic and Antibiotic can be worth trying, but this normally have some side effects, not to play around with without carefully thinking over what to do.