freaking out!

So I'm 4 days late! All tests negative until today I get a extremely faint line, so faint it can barely be seen but it's there! If I'm pregnant then shouldn't I be getting super positives by now beings I'm already 4 days late? I'm so confused and scared. I haven't had ANY symptoms besides slight cramping and I kept thinking it was af coming. 
What should I do? 
Would the hcg be too weak to show on a blood test if I called my dr beings my test is so faint? 
I'm so confused :(