This game is not meant to be easy, especially at the beginning, disease is not a difficult part though, and a cheap mask would protect you.
I doubt someone diseased you on purpose, you probably got infected by standing too close to some of the dead bodies, and even if so, just get a mask and be done with it (or berry juice).
Also dying and "making a new char" is an integral part of this game,
you may very well just do base building and character development, and with a bit of luck never lose a character, but not without missing many parts of this game.
If that is already too "much hassle" for you, then maybe Salem is not for you, go play some easy game instead.