Am i pregnanct?!!??

What's the latest time anybody has received a positive on a pregnancy test?? I took 2 hpt and they both came out negative, and went to a pregnancy center and it also came out negative. But my period was due almost 9 days ago now and i am experiencing light cramps, headaches, nausea (but no throw up), and then tonight i started getting pretty dizzy, and i have heavy watery discharge. Do you think there's a chance i'm pregnant??