Overly worried?

So, I know it’s normal to worry about your children and their health, but I can’t help but feel that I’m OVERLY worried about it. We live in central Oklahoma, so allergies are bad as long as the trees are green. My three year old has had a very slight cough for about two weeks, and I have a five week old baby. And when I say slight cough, she coughs maybe three times a day, no fever and nothing else wrong with her. I find myself spending HOURS googling symptoms of pertussis and worrying that she may have bronchitis or something of the sort. I feel like I’m going crazy. I’ll feel her forehead and she’ll say “mom, I’m fine”, but I’m constantly worried sick that she’s ill. We have a check up for both children on Thursday. But am I being outrageous?..