Honestly, sometimes you'll cry because you're stressed about what you're doing and everything that is conveniently going badly at home simultaneously; and sometimes you'll be having a great week and your teacher will decide you need just one last go-around before the weekend so you can spend the next two days re-thinking every interaction you've ever had. I've had to come around to the idea that crying isn't a sign of weakness, because otherwise I don't think I would have come back after some of those weekends.