You are definitely in the right place here, if you back up and read this thread. That 5-10 minutes is a funny thing. The actual radiation takes about 1 minute. It literally took me longer to get undressed and dressed again than to get the radiation. Overwhelmingly the biggest side effect I have seen is fatigue.
I know you have been at this thing for a while, I am glad you are finally being able to move forward with a plan.
How are you feeling now?

I had IDC in the right breast, but my radiation treatment was also 5 days a week for around 5 weeks. I have an olive complexion and tan easily. The first 4 weeks of radiation were uncomfortable, but didn't really bother me that much. There was no pain, and nothing wrong with my skin other than it was warm. The last week was very unpleasant. I am not trying to scare you, and you may very well have a different outcome, but I had painful blistering on the nipple. It took about two weeks to heal and it was agonizing. I thought maybe I had an infection because the first 4 weeks were fine. It's been a year now and it's like nothing ever happened other than my sentinel lymph node scar is dark colored. Don't be afraid. You will meet with a nurse regularly throughout the course of your treatment and they will be able to address any concerns. The nurse will prepare you for the treatments and instruct you on how to care for your skin. We also had one day designated as "Doctor Day" where all patients were seen by the doctor. It will be okay!