2.5 year old DS and Pre-school.

[CharlieWoo]

Hello.
My two and a half year old DS has just started pre school two PM sessions a week for two and a half hours. The first three days he loved it!
Fourth day he told me he didn't want to go and they had to call me after an hour to go and get him, because he was hysterical. 5th time he clung to me and screamed the whole way in and I had to take him home after 15-20 minutes.
Staff want me to bring him in tomorrow and stay the whole session with him reassuring him. Then eventually leaving him for longer and longer.
I am fine with this idea, but I know tomorrow he will cry and scream as soon as we get out of the car and he is so hard to comfort while in there.
I suppose I'm just wondering whether i'm to just carry on with this, or would it just be better to pull him out and try again when he is slightly older.
The last time we were there, he ended up crying as did I! It was a disaster.
Help please!