helpppp 😫😫😫

Ok so according to eve my period is 21 days late. I took a test this past Saturday it came back negative. I took another test exactly a week before last and it was also negative. My breast have been tender for about a week. My skin and hair have been getting really oily. I only have these symptoms when I'm about to start my period but I haven't started yet. What should I do? I have no other symptoms of being pregnant. And I can't tell my parents cuz I'm 16... am I pregnant?? Please help