You and Ash have only been dating for a few months, so there are still a couple things that are awkward between you two. One of those things is getting Ash to rest. As the student council president, he has a lot of work to do, and forgets to take care of himself. You told him to take a rest one day and he got mad because he had so much to do. This small disagreement turned into a big argument, so now he's giving you the silent treatment.