Period is MIA after being back for two cycles

I have probably taken ten tests in the last week - all negative.

My son is a year old (today actually 🥲) and around 10 months he lost interest in nursing as often as he was. Not sure if it was a nursing strike situation or because I introduced a third meal of solid food so he wasn’t as hungry at the end of the day. But my period came back end of October, returned in November, and now she’s missing again? Five days late.

My son started nursing more frequently this past month since learning how to walk full-time (working up an appetite I guess) and my only guess is that has something to do with it?

Anyone else experience this and were NOT pregnant?