It's his first year of school so I do know there's an element of catching everything.
He had a horrible cough for a good couple of weeks, eventually it cleared up with antibiotics. He's still exhausted and his colour is definitely off. His diet is generally good, although he's been so tired/ratty I'm not as strict about forcing the veg into him. He's also been getting more screen time recently, due to crappy weather and his own tiredness.
Reading that back I'm a little embarrassed and I'm going to get more fresh air and fresh veg into him. Is there anything else that could help? Chewy vitamins maybe?