Won't Eat

I have had my snake for almost two months. For the first six weeks he ate perfectly, without me even having to put him in the dark. But then my original box of frozen pinkies ran out and I started to buy the mice in single packs, same brand different packaging, and now he wont eat! It had been almost two weeks and he hasn't eaten!
I have given him mice three times now. I have tried increasing the humidity of his tank, feeding him in the tank, keeping him and feeding him in the dark, but he just isnt interested. Tonight he was moving about the feeding box until he smelled the pinky, than he bolted! Like it was a horrid smell! I don't know what to do.
I know snakes can go a fair bit without eating but he is getting very lethargic! I will try wiggling it infront of him next!