DS 12 months not eating at CM - is this normal

[sososotired]

I went back to work in June DS settled really well, I work in a school and had the summer off DS still had a couple of 2hour sessions a week just to keep in touch but now I've been back at work for 2 weeks and DS is not reall eating while he is at his CM even if I pack chocolate spread sandwiches :(
He has breakfast at home and then should have a snack lunch and dinner with his CM and is eating very very little like 1/3 of his normal portion and I'm worried should I be? Any one have a similar experience?

My DD doesn't eat much at nursery (14 months). I just give her a really hearty breakfast and dinner for the days she's there. I read somewhere that their appetites reduce around now too so that could be something to bear in mind for reassurance?