it's so hard to know what is really going on with anyone but ourselves. maybe he did get hit with a funk, maybe a series of good days taxed his reserves. it sounds cyclical....depression? male pms?
try to put some space between HIS Moods and you...you DID have a nice time, you DID laugh, you DID knock back a 3 pointer from downtown and you DID enjoy yourself. don't minimize that simply because he's having a whatever episode.
you made the right suggestion that he talk to his doctor. that's a reasonable thing to do! how HE decides to handle this is up to him.