Also suspect I had it in January 2020 from marathon weekend. Symptoms three days after I got home. Lost taste/smell for two weeks(like, could not taste AT ALL), bad cough. Had flu shot in October 2019. Took me almost a month before I could run without coughing. I remember at the time sitting on the couch reading reports of people back from marathon weekend saying they came back sick too, some with diagnosed flu, so I assumed it was flu even though I had gotten the flu shot (since it’s not hundred percent.) Now I am thinking it’s definitely a possibility it was COVID. Guess I’ll never know for sure.