Bless your heart! 3 sick babies is not fun I'm sure.
I know that in my small town near Abilene there has been tons of viruses going around for it to be summer. It is kind of odd.
One thing that I would suggest is when ever you take the kids to the store with you (or even if you go by yourself) is to use Clorox wipes on the buggy. I know that makes a huge difference for my family during cold/flu season.
I also try to do this at restaurants.
Also, with you going to the doc so much, be sure and use hand sanitizer on your kids often and try to keep them away from the toys in the waiting room and don't let them play with the other kids. Sometimes taking them into see the doctor means getting sicker than what you went for.
I will say that it seems like a lot of their problems could have been caused by the Strep which is something that lays dormant in the body and flairs up from time to time.
Maybe in a week or so things will settle down. I know what it feels like to want to keep your kids in a bubble. My very healthy 4 year old got a peritonsilar abscess 3/17 and was sick every week to every other week until we had his tonsils and adenoids out 6/6. He's the kind that usually goes to the doc once or twice a year and I can't tell you how many times he was there in that time frame! Uggh!
Just hang in there and know that this two shall pass.