Ay sis, 3 months delayed na talaga kahit negative ang tests, kailangan mo talaga mag-check with your OB para malaman kung ano talaga ang nangyayari, kasi could be stress, hormonal imbalance, or something else na kailangan ng proper check-up. A few of my mum friends din nag-experience ng delayed period na di pregnancy pero parang may underlying issue pala, so better to get it checked na para may peace of mind ka at malalaman mo kung ano ang treatment mo kailangan, sending you strength, sis!