It is normal if your stressed or if your in birth control
I think it's normal if it has never happened before, sometimes your period comes late because you ovulated late as well, it has happened to me before and thats what my dr told me
turns out I got my period today...light.. I don't know what happened I am setting an appointment with a doctor or is missing a month normal? It's never happened before?
I would try to take a other test since the one you had was expired good luck