Mellow and sad
Sorry about your cat, this indeed is a fine melody and I know how a song that's made by yourself can have such an impact, even if it doesn't have one on others, because it's fully loaded of emotions you've put in it while making it.
Only problem for me is that it could have been a little longer, but I guess you are self-aware about that, so as long as it represents your cat the best way you think, then I guess it's ok. Cheers.