Soph,
It does feel a bit like you can't eat anything doesn't it!

Cooked rice has one of the highest rates of food poisoning. It is even now recommended that you discard all left over rice as the risk of food poisoning is so high.

Because obviosuly sushi rice is cooked and cooled I would steer clear. I learnt this from the dietician I saw (due to GD) in Eva's pregnancy. She said the latest recommendations were that pregnant women do not eat nori rolls for this reason. I love them and am normally a big eater of them but due to this I keep away whilst pregnant.