I'm worried

Hi my name is Elizabeth . I'm from NYC. 
 I'm about 4 weeks pregnant my period is due but I mostly late a day or too I'm irregular. Now I tooken a clear blue digital test and it came out not pregnant. I'm scared that I'm not. I want to be so badly. Do I have still hope yes! 
 
My friend said she did same thing and it happened to her and she has to wait 3 days after a missed period to get a positive. I'm just hoping it happens to me too