I still miss my dog after 3 years

I can't move on from my dog. Sometimes life is going fine and then I just feel an immense amount of pain from missing my dog. It gets to a point of being unbearable sometimes but it's been 3 years and I feel like I should have moved on. Is this normal? I didn't go to the funeral my family put on for her because I couldn't bare facing it, would doing one all these years later help? I just want to stop these feelings coming back every few months as it's taking a toll on me.