I think your reaction is borne of panic, which is entirely understandable what you have gone through.
I also think there's things you can do in your own environment to keep the bugs down. When one of mine (rarely) gets a sickness bug, I suggest they spend their time in their bedroom (like all the time!), make it really nice in there like a den, designate a loo for them to be used only by them, wipe down all handles with anti-bac. The last sickness bug one of my children got no-one else got (noro, confirmed at school) in our house. If they have a cold, obviously they can't be confined to a room (more's the pity), but I give them their own tissues, their own mug, don't have them do unpacking the dishwasher or any food prep, anti-bac the handles and generally try to contain the germs. I also wash my hands every time I use the loo (not more, I'm not that fanatical but lots of people admit they don't!) and before eating, them the same. Of course, there are times that doesn't contain it, and when the children are little there's almost nothing you can do as they trail round snot-nosed, but in general, I've found upping the ante when people are ill and general handwashing and them getting older has meant we seem to have far fewer bugs than some other families and far less than when I wasn't into handwashing!
I honestly have cut down the amount of colds I get to about 2 a year through increased handwashing and taking echinacea at the first sign of trouble. I don't have a compromised immune system though, it must be very very stressful to be in your situation.
www.cdc.gov/handwashing/why-handwashing.html
I also try not to touch surfaces like the door handles in the work loos after I've washed my hands, I put my hand up my jumper and use it covered! I know other people don't wash their hands enough from reading MN threads!