Don't understand! ?

Have regular periods, 28 day cycle normally, always have. Had an AF on the 2nd while the 7th of September. Was due on again on the 30th of September. No signs at all, no cramps, no spots, all my usual symptoms. Felt sick for a few days and every so often, metalic taste in my mouth often. Been taking test but still negative. I don't understand why? Could I be pregnant or just late? It's my first child so not sure what to look out for ? close to giving up!!