The pill

I had a doctors appointment two days after my period ended. I asked about birth control and she prescribed it to me. She said something about starting it on a Sunday but I just got it in the mail and I’m not quite sure if she means this coming Sunday-exactly a week after my last period ended. I’d like to start as soon as possible but after reading the instructions and articles online, I’m not sure if that’s the best idea. I’m not remotely sexually active right now so I’m not concerned about the protection aspect, I’m starting it to see if it helps with the symptoms of my periods and I would prefer to not go through another PMS with such horrible cramps if I can help it. I’m just nervous about the side effects of starting in the middle of my cycle. What do you ladies think I should do? Start right away or wait til my next period? I’d love to hear from someone who did start in the middle of her cycle just to get an idea of what it could be like. Thank you!