He goes 5 days a week, and is always there at nap time.
This weekend has been even worse. Saturday afternoon he took 35 minutes and DP could not get him back to sleep. In the end I had to put him down again at 3:00 and he slept for an hour and a half.
Today, he only slept for 45 minutes and would not go back down - He just screamed and screamed.
But on Friday in nursery he took a nap for 2 hours.
He is definitely teething - cutting his molars - so this could definitely be the problem.