Yes my son has had repeated bouts of tonsillitis, he just wouldn't eat, especially acidic things like yoghurt. You could try some jelly or ice cream but as long as he is drinking he will be OK. Is he taking antibiotics for it? If he is he'll be better in a couple of days.
Godd luck it's horrible, my son would wake up multiple times a night with it. When I've had tonsilitis I've had to take those numbing throat sprays to cope - but there's nothing to give toddlers except painkillers.