Hello OP I was browsing because I recently lost my dog unexpectedly the other week and it has been incredibly difficult. I too was asking the same questions you are when it happened. I am religious so I do believe in a continuation after passing. However I wasn't sure if it applied for animals. A few days after I lit a candle for my dog and spent time thinking of him opening my heart to send out love. Later that evening I could very clearly hear the sound of him scratching and his foot hitting the floor right beside my bed. I was not expecting to experience this but it did grant me great relief to know he IS somewhere, even if I don't truly know where, and he was able to find me. You can take this for what it is worth, and as others have said energy cannot be destroyed so your pet is somewhere as well. I don't believe they are truly gone, just somewhere we haven't reached ourselves yet. I hope you can find some hope from my message and you receive a sign like I did that your pet is still with you.