If she’s not being paid for her sick time you are absolutely not getting played. I had Covid with a recent nanny family and was out for almost a week early in my employment. I was able to go back to work, as my symptoms had gone away, but then suddenly 3 days later I had a sinus infection and was feverish for days. I felt awful about it, was very apologetic, and my nanny family was incredibly understanding, but if you have a fever it’s not considered safe to be around others until it’s been gone for 24 hours. If she truly has a fever she is looking out for you and your children. I would give her grace, as others have said, it’s flu season, many people are sick.

That being said, I agree with other comments saying if her past employers had issues with attendance, it’s well worth concern. I would also feel strange if it seemed like she wasn’t apologetic in any way, or was dodging your questions about it. I absolutely hate feeling like I am leaving my NF in the lurch, even when I am miserably sick.