Hold on, I have notes on this.
In the last 12 worlds I have generated, covering 18 characters, I have made it to 5 doctor’s offices, 9 pharmacies, 2 ambulances and 7 vet clinics and an uncounted number of houses. In those games, I found no first aid kits, no disinfectant, 2 bottles of antibiotics, and 8 sets of 3 bandages.
After reading your post, I decided to download the latest experimental version I could find, OC-6882. I found a bottle of antibiotics in the first house I visited. And then promptly died from some sort of invisible night terror that had knockback. Second character got waylaid by an antlered horror and a zombear. But hey, the problem seems to have been solved by updating. 
I read Rot’s Guide shortly after posting my original post. Just checked it again. Not seeing any info on how to read the health condition screen. Presumably, red text means bleeding, blue text means infection, and green means something else. Can’t figure out what, though.
Anyway, thanks for the info confirming that the problem was in my build.
Still hoping someone will post tutorials or newb survival guides. I understand how the rapid pace of development makes such things difficult, but it’d be fun to see.