I've read up on it, but I'm looking more for info from people who have had it, how they were diagnosed, treatments, etc.

My mother has an issue with it. Hers is related to allergies. Her doctor came up with a theory about mono. But no, whenever her allergies are bad, sudden fatigue.

... I suggest check for food allergies, liver, digestive or endocrine system problems.

and auto-immune issues

I've been through a year of those tests. All the auto-immune panels, just had a biopsy for Celiac, MRIs, and so much blood taken. The only thing they've found for certain are small masses in my thyroid

but my TSH has been normal. At my appointment yesterday they mentioned they are considering CFS for my diagnosis. I certainly don't want that diagnosis. I'm sorry to hear your mother goes through this!