Weaning from EBF to formula

I am stopping breastfeeding and switching to formula due to my LO having pretty significant GERD. Up until 2 weeks ago, my baby was exclusively breastfed for his 16 weeks of life. I’m gradually stopping the amount of breastfeeding and pumping. It’s bittersweet, especially since this is my first (and probably last) baby, but seems to be going well.

My question is, when did other EBF moms see their cycle start back up again? I’m curious what to expect. Any tips for surviving the first cycle postpartum? I have heard it can be brutal.