I'm 12 days late!!

Shelby • 18 year old
I'm 12 days late and I've taken two cheap pregnant test and they have both came out negative, I'm starting to stress out, because I'm not throwing up and my boob's don't hurt, and I've never been this late before, I don't want to go to the doctor and waste money if I'm to soon to tell if I'm pregnant or not... What would you do?