late period please read and give me some advice! im really scared

my periods are almost always on time and start the day of or the next day. my period is now 4 days late and i noticed that my pms started late like right when my period was suppose to happen and im getting frustrated that it hasn’t started. i took a pregnancy test and it came out negative but im still worried and annoyed! im young and im scared and i don’t know what to do