I had radiation for rectal cancer. The radiation didn't make me sick but I started to have localized issues such burning at the site and intense diarrhea. My ovaries also got "cooked" so I went into early menopause. The radiation team was outstanding on providing me care as each symptom came up. You can also take a break from radiation for a few days if you need to.
The procedure itself is easy. I was tattooed (I freaked out but they are little tiny dots you can barely see) so I could be lined up every day. Once I was lined up the machine went around me twice and I was done. The machine moving only took 73 seconds (I counted). I was able to wear work clothes every day and just slip my pants down low enough for the team to see the tattoos. I brought my iPod everyday but the team found out I liked Jim Buffett and had that music playing for me every morning.
Good luck and let us know if you have any questions.