Breastfeeding and Birth Control

Yesterday I had my postpartum check up and my doctor and I discussed birth control. At the hospital I was given 3 months worth of progesterone only pills, which I just started yesterday. My doctor told me that the pills are okay but I should switch to something else when I'm 5-6 months postpartum. He suggested mirena but I'm not sure I want an iud. What are you guys doing?