Reducing breastfeeding and periods

Hello, my little one is nearly 7 months and we have been weaning onto the bottle gradually for my return to work. He now only breastfeeds first thing in the morning and before bed. Since reducing feeds my period has been weird. It first came back around three months postpartum but then when I went back on the (mini) pill it stopped- this is normal for me, I hadn’t had any periods while on the pill. But since reducing feeding it seems like I have a period every 2 weeks or so (including cramps and other symptoms). I’m presuming this is due to the hormones changing but wanted to know if anyone else has had this experience?