period/menses back after giving birth

In my first pregnancy, it came as normal after delivery as its usual. And in my second pregnancy as m on breastfeeding, it came after 2 months, and with a li'l irregularity with my date. I usually gets my periods on the same date or just a 2-3 days gap. But now it becomes 5-7 days delay every month. My baby is now 7 months