What if your period switch up days every month how do you know if you are pregnant?

It's normal for the length of a woman's period to vary from month to month. Anthing between about 26 days to 35 days between the first day of one period and the first day of the next period is normal.

It is not reasonable to expect your period to come on the same day every month.

You know if you are pregnant if your period is a week late and your pregnancy test is positive.