Hi there. I'm very concerned about my cat. He is about 6 years old and has always been a little bit overweight (nothing seriously major). In the past few weeks we have noticed that he has lost a lot of weight and doesn't want to eat his food. We have tried giving him wet food, changing his food, and even giving him tuna. He doesn't even want to eat his treats that he has always loved. Also he doesn't want to drink the water we give him. He only wants to drink out of the sink, or if we leave some water in a cup out. His dish is clean and we even bought him a new one but he still doesn't want to drink out of it. He has always been a happy, healthy, and extremely affectionate cat and only goes outdoors to sit on our balcony (never wanders or goes prowling). There haven't been any major changes recently. 15 months ago we had our first baby but he adjusted well and only recently started losing weight. I know these symptoms could mean numerous things, but what are the most common reasons for something like this?
He is still his affectionate self, and does everything else pretty normal. No throwing up, bleeding, or anything like that.
Please help we are so scared.