This thing seems to be far more contagious than COVID. I've had had it, almost everyone I know has had it, many on this forum have had it. I don't recall the flu or common cold being so aggressively spread in this country. I think it could be the new COVID variant. Testing is not very reliable with this variant. (My bother-in-law recently tested positive for COVID but when my sister, their daughter, and my other sister got the exact same symptoms they did not get a positive result.)