Should I say something or let it be?

The other day my girlfriend was talking about breaking up because when school starts back she will be super busy with AP classes and a job, and we live 40 minutes apart, and we had a rough couple of days before. But yesterday and today we have been great. I am worried that her being busy may have just been an excuse, but I have been known to worry too much. Should I say somethIng? Or is it too big a risk of me being wrong, and making things worse? :/