Should I tell me boss and go home early today?

I talked to one of my profs after class about how I’m not peforming as well as I would like, and now I’m really sad. I was crying on the way over here. My boss hasn’t come into work yet. He’ll be here in less than an hour. I know if I tell him, he’ll let me go home, but I don’t want to seem like a sissy, and I also don’t want to seem unprofessional. I don’t know what to do. I know I should get over it, but I just want to cry some more…