Thank you all so much for your help. this is the first time anyone has ever replied to me!!
He is teething quite badly at the moment, i thought that it could have been that myself, and i will try sitting him in his chair, that is a good idea thanks.
As for the teat, it is a fast flow, and the right one for his age, he has no trouble drinkning water or juice from it so i dont think that is the problem but thanks anyway.
Will try all the suggestions and sorry DJs Mummy, but always nice to know that someone else is going through the same problem as me.
THANK YOU ALL!