Pretty simple and it doesn't really need a solution but if you are wondering what to do I'll tell you. So once you load up the game and begin playing (Make sure you're able to take control of your character and quit out by pressing
then
). Make sure to check that it says continue game now and that's it you're set to go and the timer starts. Either play the game and work on other achievements or hold off on it for 28 days, do whatever you want. Once it's been 28 days (Real days), load the game back up and the achievement will pop.
You don't actually have to play the game, just load the game up is enough for it to pop. If it doesn't pop, try loading the game up all the way to where you press Continue. Press Continue and that should do it. If that's still not enough, wait a couple days because maybe you counted wrong.
Also, this doesn't have to be 28 days without playing or 28 days in a row of playing.