Not normal for me

So this month I had a weird period it was light only lasted 2 days and then I had spotting for 2 days(nothing on pads). It's weird because my last two periods were heavy and 4 days long and they were both 3 days late and this one was a day late my cycles are changing I went to talk to my OB about it and she couldn't give me any help or advice. So I'm wondering if you ladies could help I've taken multiple pregnancy tests all negative... So I have no idea maybe just a weird period?