[Miss Behavin]

When I first brought Pippi home, I was staying w/my parents for a period of ~ 1 months time, while my condo in Bal Harbour was being re-modeled. I had already 1 dog, Casey, who was ~ 13 y/o. Pippi was liberated (as I call it, so as not to feel so guilty for 'supporting' a puppy mill) from a pet store near their home. She was 3-4 months old and ageing out at the place. My mother was furious. I mean, flipped out beyond all reason. It was like she was having a nervous breakdown. One morning, I was trying to crate-train Pips, my mum got up b/f I did. She took Pip out of her bed and the poor, sweet girl was covered in her own filth . She knew nothing different other to just eliminate wherever she happened to be.
Fast-forward 1-2 months: my mum simply adores her. She is so-oo happy when we come visit & terribly sad when we go (back home). I am w/my parents this weekend and last night, my mum was holding Pip on her back, putting a clean sweater on her. My dad has always adored her.

In some ways, though, it's a catch-22. Your pup must live w/you, and you alone. And, if a few more days pass and you're still feeling lukewarm, maybe it would be best to surrender him back to the breeder. It's hard, b/c you don't know how you will feel down the line... if you'll feel guilt or regret, etc..
If it were me, I'd wait a day or two, see how you feel (don't wait too long, for his sake ). Maybe he isn't the right match? And, the next puppy you get, be sure you're able to spend time w/. En vivo, so you know for certain.

Best wishes. I do not envy your situation, but you'll know what decision is right for you