I thought my missed period was an irregular period also.. now im four months pregnant lol. Go to a womans center or something an ask to have an ultrasound done..
Its normal to randomly miss your period. Even if you don't think so. I've had regular periods my whole life then last year skipped 8 months for no reason. If you're still getting negative tests you're not pregnant after that long. Could be stress
It could be pcos causing irregular periods if your not trying take birth control pills to regulate your cycle talk to your dr