Winter sickness

At any point in the last 2 months, we've had 1, 2, or 3 sick kids.
It all started when Kendall started caughing, sometimes just a little, but other times until she literally threw up. She still acted normal, playing and eating like usual, so I decided not to bring her in to see the doctor. But after 10 days of this, I knew I had to do something, so I brought her in, where the doctor diagnosed her with the start of a pneumonia. She prescribed her antibiotics and it seemed like her coughing fits decreased, but they didn't disappear. Still, I couldn't bring her to the gym, playgroup, or church for 5 weeks.
Once she was better, we went to church, but that week, Taylor got hand-foot-mouth and a fever that went up to 102.6 a few times. Being an extra contagious disease, we were lucky Kendall only got a mild case of it while Logan didn't get it at all.
The next week, however, we noticed that Taylor's lymph nodes were enormous, so I took him in to see the doctor. Since Kendall still coughed, I brought all 3 kids with me. The doctor checked for strep and mono, but Taylor's tests came back negative. So she referred him to an ENT, who prescribed him some antibiotics.
Well, the poor boy who was already sick must have caught another bug while we were at the doctor's office because he started another fever and he also started throwing up. This time he was not feeling well at all, because he laid in the couch all day for 3 days and refused to eat anything during that time. All I could do was hydrate him. To make things worse, Kendall and Taylor got the same thing on day 2. They, however, got over it after 2 days. It took Taylor a little longer to start eating again and even longer to be active. As if he wasn't super skinny already...
We had even planned a trip to Maryland that we had to cancel because the kids were squirting stuff from the front and back. Anyway, we've rescheduled that trip in a couple of weeks, now that the kids seem to be doing better. I just hope that they are done for the season. It makes me nervous to go back to church, playgroup, and the gym. But I can't shelter them all year around. We've gotta get out of the house, do things, and see people. I just cross my fingers that people out there are being smart about keeping their sicks kids at home, like I did for 2 months.