Awww…I sooo get it and I’m sorry you’re going through it. Grief is hard enough without feeling like you’re supposed to just get over it. I agree with @longgone. Talk to your dad and try to explain how you feel, while also letting him know you appreciate him trying to be helpful. although, if he’s the type of guy who’s all macho and wouldn’t get it, maybe keep it to yourself.
Bonding takes time. Even if we’re not in a grief period, not everyone just immediately has that special feeling in their heart about a new animal. Animals are the same way…they ‘love’ us instantly because we give them attention and food and playtime, but even they don’t have the bond with us that they’ll eventually develop.
The best I can say is to take care of you, really. Try not to feel guilt or ‘shoulds’ about the puppies, or to force yourself to feel something about them that you simply don’t just yet. They’re getting everything they need from you and your family and are quite happy. You have loads of time to grow closer and develop those bonds that make them special.
And keep coming here and unloading. We get it. {{hugs}}
p.s. on the right side of the page are previous posts about animals. It might help to read some of them.