It could be thyroid related, or something else entirely. But whatever it is, it can likely be helped. As a human who takes thyroid meds every day, I know it can be controlled. Definitely a vet visit is in order. If you do not have a regular vet, call around and ask if anyone can work out a payment plan, and explain the situation. And you are not a horrible person! Welcome to Pet Talk, I hope it turns out to be something easily manageable.