Got my DAMN periods at 4 months PP!!

Abi

I'm so shocked to see that my period is back. My daughter is only 3 and a half months old. And I'm EBF. Haven't even started solids yet. It's my second child. During my first pregnancy I got my periods around 9 months PP. It seems too early. I don't pump. And my daughter she sleeps for around 5-6 hours some nights. Did that make it happen? I'm worried whether this will make my milk supply drop. Also this period pain is making me hard to look at my toddler and baby. I was so happy that I won't get it sooner. Now I'm almost about to cry. Please suggest something about this.