Ay, possible talaga lalo na kung sexually active kayo, kahit regular cycle mo before, a few of us moms were shocked na nabuntis ulit kahit hindi pa fully regular ang period after giving birth, kasi ang breastfeeding and postpartum hormones ay nakakaloko talaga! I'd suggest kumuha ka ng pregnancy test or mag-check with your OB para ma-confirm, kasi 10 days delayed is worth checking especially pang peace of mind mo lang.