I'm very sorry for your loss and agree with what everyone has said.
I've had to make that tough decision with two of my pets. And yes, my heart broke and I felt worse than awful. But, it really does get better. You need time to grieve. It is completely normal.
I do think a new pup is a good idea. Maybe not right away, but start thinking about, looking for the perfect breeder, shopping for the new puppy, etc. It will help you look to joyful things and feelings.
Best to you and lots of hugs.
