How to move on socially and mentally?

It's normal to grieve for your pets. I would be a basket case! But five months is a long time to be so sad. I hope you're not feeling overly guilty or anything like that, because really when animals, or people, get so old, it's natural that they p on. It's actually a blessing sometimes. Maybe a new Chihuahua puppy for you and Tia would be a good idea. Tia is innocent and just needs love, too.