My period is a week late

Alicia

I am over a week late for my period, 8 days to be exact. I've taken 2 pregnancy tests, both have been negative. Do you think I am just having a late period or am I possible just too early to tell? According to my calendar I was supposed to ovulate on the 25th. My period was 10 days long and started on the 9 th of last month.