Ladies do you see anything?!!

Idk what to think... I'm so sad... I posted a few days ago because I took a test on the 7th and it was Neg and then re tested on the 9th and at first it was negative I came back a few hours later and there was a second line!!!(but the change did happen way after 10 mins) and today I tested again and I got another negative... But I haven't got my period... My cycle is every 21 days so my period was projected to come on the 24th of March (my last period was on the 3rd of March) and since I missed on the 24tb the next projected period was on the 3rd of April and nothing and then on the 10th and still no period... What should I do????