Its the scourge of daycare as far as I am concerned..and I am a provider. Many Dr's (here anyway) tell parents in the last few years...no meds needed, blah blah. Well I have my own rules, based on my 14 years in group setting home daycare. Meds AND no goop, or keep them home. Its the only way I can keep it contained. That and a wish and prayer that all of the disinfecting, bleaching, etc works. I Lysol every doorknob after people enter and leave my home...inner doorknobs after kids go in and out of bathrooms, etc..wipe down sinks knobs and flushers...I go maniac on it as I have had it go around and around for months before.
I have been told that dogs get it alot (consider how they scratch their eyes..we pet them on their faces, etc) and we can spread it back and forth...so not sure if you have a pet? but its a source as well that many don't consider.
Just keep what you are doing...wipe down and Lysol and wash (HOT water, soap, bleach if needed) any and all surfaces you touch. Remote controls, keys, your toothbrush handle...the drawer pulls, doorknobs, your phones, I even do the little plastic pulls on the window blinds! The banisters (my daycare kids touch them down low to walk up and down the steps, so a different perspective as well if young children). Its an exhaustive list, but sometimes really necessary if its getting out of hand like you are describing. I have been there...
Best of luck to you!!!