So your kid is sick and you are calling your doctor. You can be assured that a few things are bound to happen. At least, I know this is how it tends to go for me.
1. Your kid will be sick at the most inconvenient time possible.
Maybe you will be traveling in the next few days, maybe there is a huge project at work, maybe your spouse will be completely unable to get any time off of work to help you, the driveway is covered with snow and impossible to leave, or maybe a major holiday is right around the corner... or heck, maybe they are sick on that holiday. Whatever it is, kids never get sick at a "good" time.
2. There will be a problem scheduling your appointment.
It may be a weekend so you have to go to a walk in, or your doctor is on vacation, or they are completely booked for the rest of the day, or the phone lines are down for the morning and only emergencies are being put through. I've had all of those things happen to me in the past two weeks. No matter when I call there is always an issue.
3. By the time you get there your child will be the picture of health.
When you called the doctor your child was screaming, not eating or drinking, puking, had a fever, a cough, and was basically a complete and total mess. The doctor told you to give them some Tylenol and come in for your appointment at the scheduled time. You give them the Tylenol, load them in the car, they pass out, and by the time you get there they have rested and their fever has come down. By the time they call you in for the appointment your child is trying to escape your lap and run over to play with the germ infested toys. "I swear I was not making it all up. She was really, really sick." And then by the time you get back home the Tylenol has worn off and you have picked up the prescription for their ear infection and pulled into your driveway the fever has come back and they are sobbing. Because that's just how it works.
4. The healthy sibling will catch something entirely new from being at the doctors.
You bring the healthy sibling(s) to the doctors with you since no one was available to watch them or was ignoring your phone calls in fear of catching your germs. Either way, healthy child is coming with you. While you are trying to wrangle sick child, healthy child is socializing with the green faced stranger kid and touching the germ infested toys. You wash their hands, cover their bodies in sanitizing lotion, but it's no use. Two or three days later healthy kid is now a sick kid and the whole process starts again.
Any way it goes, having a sick child is one of the toughest things in the world for a parent. Even if everything goes right it's still hard and know that somewhere I am raising a glass of caffeine just for you. It's gonna get better, I swear.