Hiii, ang ingat mo talaga with protection at pull-out pa, so honestly you're likely safe, four negative PTs is pretty reliable, lalo na ngayon at 29+ days na delayed mo. The light bleeding that came after could just be your period arriving late and lighter than usual, which happens sometimes from stress or hormonal changes, kaya don't panic! But if you want peace of mind talaga, punta ka sa OB para proper check-up lang, especially kung weird pa rin ang cycle mo sa next months, better safe than sorry, diba? You did everything right, mama, so breathe!