A Mom's Work is Never Done

So if you come and visit our site very often, you notice that I change it up all the time. We think we've finally found a template that we both like. Matt never puts anything up, but he didn't really like what I had chosen for the whole look thing. I think we've found something we both like now.
Anyway, life has been crazy the last few days. On Sunday we noticed some blisters on Jackson's mouth, and by Monday evening he started fevering. Tuesday morning we were able to break his fever, and by school time, he seemed well enough to go. He was laughing, playing, and had no obvious sick symptoms. So, I sent him. By Tuesday night he was fevering again. When he woke up on Wednesday, he had little red bumps on his face that resembled chicken pox. I was a little nervous because Jackson had been vaccinated against chicken pox, and there weren't very many bumps. I was confused. I took him to the doctor, and it turned out to be strep. Needless to say, he won't be going to school for the rest of the week.
Being a mom seems to be a lot of "guess and check" work. Many people have written books to help and give advice, but I still feel like it comes down to "Mother's Instinct." Sometimes I wonder if some moms have more than others. Am I too easy going and not worried enough? Do I worry at the wrong times, when I don't need to be worrying? If any of you moms have great advice, I'll take it.