My period was due five days ago (Monday) and it hasn't come. I took a pt on Tuesday and Thursday afternoon and they both came back negative. Today I have noticed a whitish discharge and a little cramping. I have a 6 month old baby and I'm 21. Could I be pregnant and still be getting a negative test?

Its too soon to take a test. HPTs are less than 50% accurate during the first week after a missed period. This rises to over 95% at the end of the second week.

So yes you could be pregnant.