Loads of good advice already, so this is more of a hug and reassurance from me that it
will get better. There is no rule that says you must love your puppy whole heartedly right from the word go! There's no rule that says you're a bad person if you have doubts and feel exhausted and frustrated!
Puppies aren't even just hard work. They're life changing, needy, time consuming little horrors a lot of the time and it's very hard to see beyond that and very easy to have loads of self doubt and to beat yourself up endlessly.
I know, because I'm just beginning to come through that stage with 18 week old Louis. He isn't a biter, so I know I've been very lucky in that respect, but he's like a little hurricane in the house and garden, was difficult at night for the first several weeks, still isn't great with house training and is endlessly and remorselessly in my face and under my feet apart from when he's asleep. Added to that, my 5 year old Cocker Spaniel, William, doesn't like Louis and ignores him, so hasn't been much help in keeping the little g*t occupied
It's taken me until now, so about 10 weeks, to start bonding with Louis and loving him, as opposed to just looking after him. He's suddenly started turning into a responsive little chap, who (sometimes) is on the same planet as the rest of us and wants to fit into the household instead of living in his own little Louis world.
Keep talking on here, because there's so much support and good advice that will help you through
