Should I be worried?

Ladies today when my SO got off work he looked all stuck up. Well I kept asking what was wrong and why he was acting different. He then replied "You wouldn't understand" so I kept telling him just tell me. He then said "Its like nothing seems to interest me anymore playing games, watching tv, going out places or even caring what people have to say."Like he just fakes his faces and attitude. So when someone tells him something he acts like he cares but just doesn't. He said that how he feels everyday and he was acting like that because thats how he feels like being but instead he acts all laughing and smiling but really that's not how he feels. He said he doesn't even see the point of anything anymore. I asked him if he thought about hurting himself and he said no" he said the only thing that really interest him is us cuddling and talking sometimes. I also said something about life and he said "What is life"