Hello my periods are always the same every month . this month it was late and two days long what could this mean?

Normal variation: It is common for the cycle to vary from time to time. A few days difference in start time of menses should not be worrisome. The intensity of the menses can also vary so it should not be alarming to have an occasional lighter (or heavier) period. Of course, there is always the possibility of conception if you are sexually active - so if there is concern it would be proper to check a pregnancy test