Teething?

Today Alex didn't go to daycare so Mum stayed home with him. He's had a fever for the last 24 hours and has generally just been a bit sad and quiet. It's all a bit confusing because once again he has a cold (he's pretty much had it since we got back from NZ) but I'm pretty sure that I can see a new tooth in the top (an incisor). Also, he's been playing with his mouth as though he can feel something new too.