I am a 21 year old female I had my last period on June 11th I am now 12 days late and have taken 2 Hpt's and both came back negative... I have been having lots of head aches and my face is breaking out (which NEVER happends to me) I am tired all day and feel nausious all the time throughout the days I am waking up even during the night to use the washroom because I have to pee all the time... now I'm sure a lot of you are thinking "ok, this girl has all the classic syptoms of being pregnant" and I am fully aware that yes it does sound like I might be pregnant but the thing that throws me off is the negative tests... and I have no signs of my period coming (usually we can tell right) anyway I am just looking for other oppinions or experiences, or has anyone had these syptoms and had it turn out to be something else? Or do you think I am pregnant and the tests are not reading right?
Thanks for your comments, I'm sure they will all really help me.

I forgot to mention when my period was due I had half a day where I had very light pink blood only when I would wipe, I hear that's called "implantation bleeding" could that be something besides implantation bleeding??

It would only be implantation bleeding if an egg was indeed implanting, and many women never experience any sign of this.
It could be you are pregnant and test just haven't picked it up yet. Be sure to follow the directions on the test exactly. You might want to check with your doctor about having a blood test, or you could wait until next month and see if you miss another period and test again at that time.

Might be an off cycle where you will be late or skip it altogether.

If you are usually very regular, and since you have a few possible symptoms, I'd see your doctor, explain the situation, and ask for a blood test to be done.