Taking a mental health day?

So I texted my boss saying I was sick and won't be coming into work today or tomorrow. In reality, I just really needed a mental health day. Everything is overwhelming right now. I'm a full time student and only work 14 hours/week, but it's still a lot to do. My boyfriend is going to be upset when I tell him I'm not going into work because he thinks that I just don't want to work. He won't understand.