Hindi ka lang, maraming tao ang nakakaranas nito talaga! Five days before your period or delayed period, both are actually pretty normal, lalo na kung stressed ka, may changes sa routine, or hormonal fluctuations lang, kaya don't stress too much about it. A few of my mum friends and I noticed na ang cycle namin ay hindi laging predictable, especially pag may pagbabago sa diet or exercise. But if you're really worried or if it keeps happening, best check with your OB para sure lang and para mapakali ang isip mo.