So sorry for you right now, really feeling your pain.
I know what your talking about as I lost my beloved dog in January.Had her for 11 wonderful years ! I was still drinking at that point and I don't think I got out of bed much for the first week. Was so heartbroken but as you said, the guilt and shame of the drinking probably made it worse and it did accelerate the drinking - infact it's taken me until June to come out of that particular mess.
Without drinking, I can think back now more clearly and while I will always miss my best friend, I also realise that you have to deal with the pain without that "prop". Taken me forever to work that out.
I understand your message completely, thank you.
Hope you have good people around you for support.