Ay, 13 days delayed na? Lalo na kung regular ka talaga before, that's worth checking with your OB agad, especially since you're 10 months postpartum pa lang at nagbreastfeed ka pa. A few of us mums nakaranas ng delayed period habang breastfeeding dahil sa hormones, but better safe than sorry kaya punta ka na sa doctor para ma-rule out kung may iba pang nangyari. Fingers crossed it's just hormones, pero don't wait pa if it goes longer!