thanks for the replies ladies..

All that i have been offering him are his 'fail safe' meals and he won't eat them, flat out refuses. In fact all he has eaten today is a tub of yoghurt and 1/2 piece of toast.

We even made chocolate cupcakes today (A total treat for him, as usually I just make healthy muffins), he helped mix them and decorate them, and yet he totally refused to eat one, wouldn't even take a bite, and that is a huge thing as it is really not like him at all because when I rarely make treats like that, he will scoff them down and be asking for more

I guess i'm just upset and worried because it was litteraly overnight that he started this and its getting worse

Thanks for the V8 juice suggestion GG, i will try that and maybe the multi vitamin, but not sure how to get that into him.