It's causing a lot of stress when I get back home. Wondering if I somehow inhaled it from someone, only feeling relief many days later when no symptoms developed.
You are suffering severe anxiety, as long as you take the recommended precautions it is going to be very unlikely that you are going to catch the coronavirus, instead of taking a look at the world statistics of contagion you need to look at your local statistics, once you do that most likely you're going to find out that only a small amount of the population have contracted the virus.
And most of those people are keeping themselves on their home so the chances that you cross with one of them is very low and even if you do it is unlikely that you are going to be infected by them.