RE: I regret getting a puppy and I don't know what to do.
My mother-in-law adopted a chihuahua from a local rescue. Within about three weeks she regretted it. She did not realize that he would take so much work (he came from an abusive situation). He was a fear biter and was not disciplined at all. He did not want to be on anyone's lap, did not want to be held.
Long story short, she asked me to take him (because I was the only one he had not bitten). I hesitated because I had an awesome dog and I did not think that any dog could ever take her place.
But when it came down to this little guy going back to the rescue or coming home with me, I relented. my husband was very apprehensive. At first he had said no way (the dog's nicknames were devil-dog, Cujo, Killer). When I began explaining the way the dog was thinking and how that was affecting his behavior, my husband gave in.
Today we have an obedient, sweet, cuddly little lap dog who hasn't even tried to bite in a long time. He is submissive to the humans and he has found a place in our home and in our hearts.
He isn't my old dog and he does not fit in that space. He takes up a new space. Let that puppy find it own space in your heart. You sound like you are concerned for the dog - I suspect you will come to love him.