Am I pregnant?

I am 4 days past my missed period but I've taken 3 tests and they are all negative. Periods are fairly regular, usually 29-32 days. Still no period in sight, I get pretty tell tale symptoms and haven't had any. Everybody tells my I'm just stressing about it and that's why I haven't gotten my period, but I don't really feel like I'm stressing at all. All the tests I've taken have a high sensitivity as well. What the heck?!