If your period started at the end of the month and ended a few days into the the next month but you didnt get another period until the next month does that consider as a missed period?

The cycle should not be always 28 days, it can be up to 35 days.

I would not consider that as a missed period.

How long is it from the first day of one period to the first day of the next period? While the typical span is a month, this can vary from woman to woman and from month to month. Normal periods can be from 3 weeks to 5 or 6 weeks apart. If you have reason to be concerned about a missed period, suggest a pregnancy test. In this case, the period came the next month.