Good afternoon, i missed my period however the 2 pregnancy test i did came out negative. what could cause the miss period?

It depends.: It depends when you did the tests. If right at your period, they can be false negative. Stress can also cause a missed priod. A condition known as polycystic ovarian disease can also do this. You should repeat the pregnancy test in a week. If it's negative or you didn't have your period, go see your doctor for tests, etc. To find out the cause.