I suspect a lot of these flus are Covid... I just got Covid recently, but I only felt ill for maybe two days. I only tested myself because I'm in a choir that requires testing for certain rehearsals, otherwise I would have figured it's "the flu" or something. The guy I sat next to this week said he had a similar illness a few weeks ago, but he didn't test himself and attributed it to a random cold (but was surprised he's had lingering symptoms).