Ay sis, stress and breastfeeding can really mess with your cycle, kahit na yun pa lang nangyari sa akin after my second, delayed ng ilang months haha! Since negative ang PT mo last July 6 and you're still waiting, I think best to follow up with your OB para ma-check properly kung ano talaga ang nangyayari, especially if it's been that long na, could be hormonal imbalance, thyroid stuff, or something else na kailangan ma-rule out. In the meantime, try not to stress too much (easier said than done, I know!) kasi yan talaga ang nagpapagulo ng periods natin moms