Sons anxiety over school

My son started at primary school reception last September he  seemed to settle really well and we are told he is doing really great. 

Over since February half term until the end of last term he seemed to be getting very very anxious in the morning ( for the record there is a tTeacher there he hasn't taken to which we are working with the school to improve this) 

However our son has developed a stim where he says Over and over again "not today" and "its the holidays" its affecting him deeply it wakes him up at 230 am and he says it all day long.

As a family its taking its toll on us all and I just need some tips on how to handle it and signposting of who I can speak to as we just cant go on. 

Can anyone help ?