Problem with feeding new BP

I am totally new to BP. Had a corn snake years ago but never had a problem with feeding him. Just came home with a BP a couple of weeks ago from Reptile Expo. Came home with him on Sunday. He was supposed to eat on Tuesday, and there was no problem. I fed him a hopper rat. It took him a few tries and all was well. I brought him in his tank right after. I noticed that he didn't poop as much as the prior week. Tried feeding him another hopper last week on Wednesday and he refused it. I left it in his enclosure all night. Even though I heard him move around at night, he didn't eat it and I threw it out.

Now, I wanted to feed him (he is about 2 feet long, 1 year old) today, but he was so lethargic yesterday. His eyes are sort of milky and he is laying in his water dish a lot. I guess he is getting ready for a shed. But should I try to feed him today anyway? Can't get a hold of my seller any more, I got out too late from work. Can anyone help me with some advice?

He didn't move around much yesterday and it feels like he lost a little weight. He doesn't feel as solid as he did before. His body is not yet milky, just the eyes.

I would start here:
http://ball-pythons.net/forums/showt...-With-Pictures!

And here:
http://ballpythonbreeder.com/2014/8/...thon-appetite/

Also contact the prior owner and find out whether or not yours typically eats while in shed.