Starting in June, my periods have been 10 or more days late, with the longest being 17 days late. Then when I finally do start I count 28 days from that day, and figure out my new cycle. Then the next month rolls around, and I am 10 or more days late again. I have taken multiple pregnancy tests, and on month 2 when I was late again, I went to the doctor. Everything has come back that I am not pregnant, could something else be going on? I have always had a pretty reliable cycle, down to the hour, and then this happened? I have no idea what is going on.