One of the most difficult and important parts of grief and loss is seeking to understand what has happened and that what you are feeling is all right. Your sense of loss may encompass your life and that is all right. You have that right to grieve and you can take as much time as you need. In a busy and demanding world, the trick is to take the time. There are many stage of grief, and none of them are absolute.
Time frames vary from person to person.
Ideally these sages are supposed to progress from stages one through five in predictable fashion. But often this just doesn't. You may find yourself very close to resolution when a memory or anniversary of your pet. Give yourself time. If you feel that time is passing too painfully for you or you want some very special and caring support, there are many sources of support available to you.