miszcat

I don't think u are a bad master.
btw cats sleep about 2/3 time a day
If u go out, your cat just sleeping,so it don't feel lonely
and also your cat is now about 80 years old, it will sleep more time
But about the problem its getting thin
u need to check if it has eat food or not
If it is getting serious,u need to pick your cat to see the vet
hope can help u

PS. my english is not very good,sorry

miszcat

I don't have a cat,but my bf have three lovely cats,so I know something about that.@@"
I get your point, but I think that if you regret something that has happened,it would be better to take a good care of your cat now, the most important thing is not to leave him/her alone again.
However,I suggest you'd better to find an animal communicator and find out what your cat really needs.I have seen a case in internet as same as yours before, but it is more seriously.it was about a girl who need to leave home for year because of study,after she came back home,her cat attacked her and angry all the time.Finally that family found an animal communicator to help them,,after a while of communication, that cat decided to forgive his master, and restore the previous nature.So I think this is the best way to solve your problem.