Birth control

I'm about 11 weeks PP and I have been on birth control for 2 months now, last month when it was time I got my period with some delayed bleeding a few days after it was over. Now this month I'm almost ready to start the next cycle and no period, is that normal? And no chance of pregnancy to busy and tired to do it. I'm breastfeeding so I'm on the mini pill not sure if that makes a difference but just curious as to why it's 4 days late not that I'm complaining. Thank you