why are you so upset about this? her son had an exam and you all were visiting and she may have been stressed about it, that's all.
let it go, as this is your family and such small incidents should not come in the way of something that is so important. i don;t think that she has changed her attitude towards you at all, it was just one day. and you yourself said 'for such a tiny thing.' then let it go, right? :) and don't think so much.
Read more