Postpartum period come & gone?

Molly

I had my little girl in December and got my period back in late March. I have been exclusively pumping for four months and on the mini pill. I have gotten my period every month but it’s never regular.

I was due 10 days ago but still nothing. I took four pregnancy test and negative. Can periods just go away again with exclusive pumping?

Nothing has changed in months, I pump 5-6 times a day and on the mini pill

Any ideas? Thoughts?