MB really weird reaction to me telling her I'm getting sick

My NK has been sick since the weekend, and finally today I felt like I was also coming down with it. It's not bad, just a sore throat and sniffles, and I'm planning to work through it especially because I caught it from NK, we're all exposed, we're just chilling at the house since he doesn't feel well - it's not a big deal.

HOWEVER. As a courtesy because I'm about to be sneezing and coughing all over her house, I told MB I was getting NK's cold, and she looked at me funny and said, I am not joking, "Nanny, you need to work on your immune system."

I was shocked. I kind of laughed it off and said I drink lots of tea, eat healthy, take my Emergen-C, but I'm in NK's business for 8-10 hours a day, it's inevitable. MB said she spends more time with him and she doesn't get sick. (Ever??? Which is also just not true.)

I felt really bad. I felt like I was in trouble and I shouldn't have said anything. I always offer to work sick unless I literally can't leave the toilet as long as NK and I can have a calm day at home.

I was sick a month ago and told MB my symptoms and that I had very likely caught it from NK and was ready to work, and she told me to take two sick days. It felt like today she thought I was angling for more time off or lying or being weak or something. I really just wanted to be honest and do the right thing.

TBH I am still reeling at this one. I can't just??? Not get sick??? Like I work out, I eat healthy, I drink water and wash hands often. Kids are going to share their germs. I feel insane, y'all.