Drooling two year old

Hi ladies and gents,

My little one who is due to turn two this month, has just started drooling heaps! He's been out of sorts this past week, a little off his food, chews on his bottle teat.. I thought he had all of his teeth :-/ but then I heard someone mention "two year molars".

He will drink plenty of milk and water throughout the day and he is eating, just not as much as usual. He's also been crying in his sleep and shoving his finger in his mouth and chewing on it.

It's just been the past week. I thought maybe he doesn't have all of his teeth after all :-/

What do you all think it may be? New teeth or something more serious?