is this just stress or something else? (warning this may be tmi for some)

ok ladies I need advice. usually my periods are pretty normal. I get one in the beginning of the month and one at the end of the month. they usually last about 4 or 5 days and usually start off heavy and very crampy (especially when they start at the beginning of the month) and slowly wind down to light and no cramps. eventually ending only in light brown spotting. that being said I have had a few months in a row where they start off with little to no cramps and only light brown spotting and don't get as heavy as they usually do. when this happens it is also a few days late. idk if this is just stress or something else. anyone else ever experience periods like this?