10 day early cycle

Caite • 22, on a baby journey. ❤️❤️
I'm 6.5 months PP. 
I got my cycle 2 months PP, even breastfeeding. I fell back into a normal cycle schedule starting my cycle on the 28th of each month. The last 4 months I've started on the 28th and lasted 6 days, (which was how it was before I conceived) 
However, I started on the 28th of January, usual, cycled 6days, normal, with normal flow. 
But, I started another cycle 10 days earlier than my next estimated cycle. 
Please offer any tips on this. I'm so confused.