Period six days late, two negative tests, no symptoms;?

My usually regular period is six days late today. I've taken two pregnancy tests, one last night and then one this morning right when I woke up - both were negative. I've been pregnant once before; I found out when I was six weeks after having no symptoms but a prolonged period that led me to a positive pregnancy test. About a week after finding out that I was pregnant I began having horrible morning sickness and migraines. I have had no changes in my lifestyle nor am I stressed... I've done a lot of reading that it could be too early and that's why I'm receiving a false positive but the first time that I was pregnant, I didn't even fully put the "cap/lid" on the test when the digital "pregnant" flashed on the test. We used the pull out "method" on September 26th and that was the only time I had sex last month. Any suggestions? Thanks in advance!