I ve had a normal cycle of 28 29 day cycle and my periods last 7 days but last month it lasted 5 days and this month my cycle was 37 days but my peri?

This is not uncommon. The most common things to affect the menstrual cycle are pregnancy or stress of any type. Any type of physical or psychological stress can affect when and if an ova (egg) is released. Moreover, it is not uncommon for a longer period to eventually be associated with more menstrual bleeding as there is a longer period of time for the inner lining of the uterus (endometrium) to accumulate.