I feel for you and know what you are going through. I also hate to board my cat, not because of health problems, but because of his intense hatred of all other people and just a high-maintenance personality in general. I always worry that he’ll be hard to take care of.
Here’s what I repeat over and over to myself before I have to board him, and maybe it will help you, too.
He’s in the best place if he gets sick. (And in your case, your babies already need medication) The situation would be unthinkable if I had a friend come in to feed him and he needed to go to the vet. He will be surrounded by professionals who take care of animals day in and day out and know what they are doing.
He is a cat, no matter how much I prefer to think otherwise. After I leave, he will settle down and probably sleep most of the time.
It’s only temporary.
Write down each cat’s medical needs, possible issues relating to each cat, just ANYTHING you can think of. Insist that they read it and are aware of everything. Find out who will be taking care of them and make sure they are completely aware of any issues. Take their own food, enough for the duration. Also take their favorite toys and a towel from home. Give them your phone number and a local friend or family’s number. Call them regularly to settle your mind.
And I’ll be honest with you. Once I’m on the road, I do relax and have a good time. As Debinoz said, a break is good for us sometimes.