If you can answer "Yes" to any of these questions, then maybe you shouldn't be going.
1. Are you a member a totalitarian party? (Communist Party)
2. Are you a former Nazi or committed acts against humanity?
3. Are you a drug abuser?
4. Have you been convicted of a heinous crime (abuse, domestic violence, etc)
5. Are you a polygamist?
6. Were you previously removed or deported from the US?
7. Have you committed Espionage or sabotage?

Most of these are ridiculous. It's pretty straightforward. Are you a criminal? Or are you a state criminal?

You'll be glad to see your family and friends that you've haven't seen in years. And in the end, you'll be back in class and remember that you did something that you couldn't do before and you'll soon be able to do again. Bom Viagem!