How do I get my puppy to behave better?

It's just my mom and I living together in our huge house and she is always taking vacations with her boyfriend, so she and I made the decision to adopt a puppy to keep me busy while she is gone. I have raised a puppy once before when I was 11 with the help of my family, but this time around it is so different. Sammy, our older Cocker/Dachshund was such an easy going puppy and so eager to please. He was the smartest in his puppy obedience class that we took him to at Petsmart in 2000. Teddy, our 2-month old Pointer/Dalmatian puppy is very different from Sammy. He bites me HARD on my arms and legs and sometimes even my face. Sammy has never bit me, even when he was a puppy. I've gotten a little too angry at times and hit him on the snout probably too hard a couple times. I just get so upset because I do EVERYTHING for this dog. I take him out to go potty every two hours, I buy him food, I pay his vet bills, I rescued him from the pound. I am just so pissed off with this animal! Not only does he chomp down on me constantly, he chews on everything he gets his paws on (and I JUST found my usb cord chewed into two pieces), he disrespects the older animals in the house and when I try to take him for a walk, he bites and tugs on the leash the entire time (no exaggeration). I could kill him sometimes. Why can't he just behave and be a sweet little puppy from time to time? He is just a monster. I am starting to hate him. What can I do!?!?