Adopted a dog today

For a long time I've been wanting a dog since my dog passed away. I've been having that itch. I finally was able to adopt a dog today. Probably literally the best kind of dog. Gets along with my daughter family and tries to play with my cat. The only thing is my at doesn't like her lol that's really it. I don't know why I'm not happy for some reason I thought it would fill that sadness of losing my dog. I look at her and still miss my dog. I feel guilty for getting another dog. I honestly just miss the feeling of having a dog the love the running around the happiness and I felt like with this new dog I was able to feel "happy" again . I just feel guilt and regret.i ended up doing an adoption trial and I really don't want to send her back because of these feelings I'm having. Will it get better? Did I do a mistake? My dog passed away in April