Hi mama! Delayed period habang breastfeeding is actually pretty common kasi sobrang demanding ng breastfeeding sa body, especially if exclusively nursing pa, ang prolactin levels ay mataas which can suppress ovulation. But since you've tested 3 times na and all negative, I'd really suggest checking with your OB para ma-rule out kung may iba pang reason (stress, thyroid issues, hormonal imbalance), kasi peace of mind lang talaga ang kailangan mo right now, lalo na may baby ka nang kailangan mo maging okay.