I think I might have had a mild case of coronavirus in February. I had fatigue, mild congestion, a dry cough, and shortness of breath from normal walking. My fever was low-grade (about 99, which might be a little high for me, but still under what most doctors look at for a serious illness). My doctor gave me an asthma inhaler. Her explanations were allergies, mold inhalation, or adult-onset asthma. No one knew coronavirus was in Northern California then, and my illness never progressed. I did end up taking some antibiotics in March because I thought I might have an infection in my tooth where I lost a filling, because I still had fatigue and throat irritation that wouldn't go away. I am glad a took them because who knows, what if I developed a bacterial infection on top of the virus? I say this because a few days into my course of antibiotics I suddenly started blowing out and coughing up "gross looking" phlegm - the yellow/green kind, not normal clear or white mucus. This went away within a few days.
I now have normal energy, no fatigue or fever, but some days I still have a light cough, which very well could be allergies. I don't usually cough from allergies though just blow my nose. It's typically only in the morning, or if I use my space heater, the fan might irritate my lungs. I really don't have any other symptoms and the worst of what I felt in February or early March is totally gone. No shortness of breath.
I have no idea because no one around me has developed a serious case of COVID-19, and there are only 52 cases identified in my entire county, mostly from people who traveled from China, San Francisco or LA. I could have easily gotten a mild case though from a student traveling from the San Francisco Bay area back in February since I live in a college town.
Or maybe it's a coincidence. I am not taking chances though. I am not trying to catch it if I didn't actually have it, and if I am/was contagious in any way I don't want anyone to catch it, so I still isolate, social distance, and wear cloth masks.