A week late but negative tests

So I was suppose to start my period on the 8th. I took a test 4 days ago and it said negative. So I figured maybe it was just a little late. I flux by up to 3 days usually. Today I woke up and still nothing, so I took another. It still says negative. Has anyone who's usually pretty regular had this happen to them? I'm not sure what to feel. I usually cramp a day or two before and still nothing. I feel like my stress levels are lower than they've been in months so I'm not sure what else this could mean.