Is feeling like you have the flu always considered PEM or can that be a symptom?

I feel like I have the flu for a significant part of every day. Sometimes it's more mild like right now, but other times its really heavy and I cannot do anything. I have not found a true baseline yet and I am 1.5 years in to this disease, 10 months of being bedbound and severe. That is because my symptoms and PEM are all over the place, no matter what I do (I do the same thing every day, which is not a lot). It is hard for me to tell what is PEM sometimes and what is just a high symptom burden.