Hey. Probably because you deleted game.prefs or created another user on single player, but anyway.
The solution (cheating) to get lots of favor points (could get favor items, but more writing/changing).
Go to my documents\my games\gas powered games\demigod\game.prefs. There press CTRL + F for find function. Write in that window "points". it should lead you to your favor points line. For example my line looks:
Points = 22915,
Here you change number to any you wish (not too high though, as I don't know the limit and what would happen if you reached it). Then save and go take your favor items