Is this the beginning?

I am feeling slightly feverish, but it can't be a high fever because I feel fine otherwise, not woozy or lightheaded. We have several thermometers, all from long ago. The battery one was trying, but it's more than 10 years old, and we don't trust it. It only got up to 97.7. The mercury one that only goes up to 100 got to 100 last night, then the other mercury one said 98 within a few minutes of the first check. This morning one of them read 99. We have called five drug stores and nobody has fever thermometers in stock, although two of the chains in Lexington (Walgreens and CVS) seem to pin their hopes on a truck that will arrive mid-week.
So we're starting the 14 day house-only count yesterday. I am wondering how I could have been infected. I have been out walking or jogging almost every day, trying my darnedest to maintain distance, but (before yesterday, when I shopped gloved and masked), the last time I was at a store was the 17th, and the last time I was in a house with a bunch of people, none of whom I touched, was the 14th.
Arthur believes he has it based on an intermittent sore throat and a feeling of foreboding, as far as I can tell. There isn't anything like universal testing, so we are just guessing. I worry that we are guessing wrong, and when we declare ourselves done in a couple of weeks, we might have had some other bug(s).
We have a screened-in porch. We have decided that being on the porch is not much more public than the Italian balcony musicians.

Edited to add:
Arthur: is there anyway you run with no people nearby?
Me: No. Maybe in the pouring rain.
Arthur: Then you would get a cold.
Me: Aren't you a believer in the germ theory of disease?
Arthur: [smile]

My sister did her own comparison. They have two mercury oral thermometers. One read 99, the other 97. They have a laser temperature meter for engine diagnostics. It was reading unreasonably low on a human instead of an engine - her temple showed 83 degrees.

Science!

Or measurement, which is sometimes the same thing. We have three mercury thermometers and one digital.
All but one of them are basal thermometers, which only go up to 100 degrees F, but are more precise than other mercury thermometers.
We have just done an experiment and tried three of them (all mercury) each, with long under-the-tongue times and short breaks in between. My three were very close: 97.6 or 97.7. Arthur's ranged from 97.6 - 98.6. I also used the old electronic one and got 97.7 as well, but before Arthur could try it, the display picture looked kind of like an empty battery, so maybe I have drained its last bit of juice. We are going to disregard the lowest one, which was 97.6 for both of us, and use the other two to take our temps daily. What one might notice from this is that we don't look like we have fevers. We both feel pretty good now, so was it some sort of false alarm? I'm way past hot flashes, so that doesn't explain it. Do we stop counting days?