10 months postpartum, babe EBF and ovulation question!

So I had my daughter 10 months ago:) I am essentially breast feeding and feeding her solids.

I got my period 5 months ago and it has been regular!

We have been trying for baby #2 since last month (I know I ovulated), but this month I don't see ovulation in sight! I'm on day 18 with no positive OPKs.

Anyone experience a missed ovulation cycle? Could this just be because I'm still breastfeeding???

Trying to rule out my thyroid condition.

Thanks!