My Apple watch reported A-Fib. I didn't take it too seriously. Then an hour later it reported A-Fib again. I let it go overnight, but the watch was still calling A-Fib when I ran the ECG function. I told my wife, a nurse. She told me to get to emerg. The emerg nurse said yup you are in A-Fib and they like to clear up A-Fib within 48 hours as the risk of stroke may increase. They did the conversion by doubling my normal dose of Bisoprolol. The conversion to normal pulse occurred within 30 minutes. Had the conversion not occurred, electric shock therapy (or whatever it is called) would have been the next step. I'm now on Eliquis and Apixaban to prevent further issues.
So, as ginnyjm says - take A-Fib seriously.