The merry go round

It's been one week since Coopers accident, one week of reassuring my little boy every day that he is safe, brave, and he will be ok.
I feel like I am on a merry go round. Every day I jump on, just waiting for the moment when Coops will mention he fell in the water.  Each time he mentions it, my heart drops out of my chest.  He stares blankly as he talks about it.  My poor baby, what is going through that precious little mind of yours?
Today he started back at creche, and I felt a bit apprehensive leaving him this morning.  I know he is safe there and loves playing with his friends, it was the factor of him talking about falling in the water without me being around.
I explained to his carers what happened to him, just so they knew and understood if he started talking about it.
He kissed and hugged me, said "bye mummy", I prayed that he would have a great day.
When I went to pick him up tonight, he was sitting in the playground on a chair, staring off into the distance.  This was not my bouncy little man who is usually running around with his friends, climbing, playing in the sand pit. I went up and said "hi Coops, how was your day?".  He responded with "mummy, today I fell in the water". That blank look, it broke my heart.  It was like he was reliving it all over again.
 It's been exactly one week and he was adamant that it happened today. He kept repeating it - "I fell in the water today, I splashed, I got wet, daddy had to save me.  I must be careful".
Bless his soul, I just want to wrap him in cotton wool, protect him, be there beside him for his every waking moment.
When will this merry go round stop? I'm tired and my heart is breaking for my gorgeous little boy.