Okay so I had my last period on 24th of July 2012 it's now 18th of September and still no period so my period is at least 3 weeks late!! I did a test with my school health nurse when I was 9 days late. But it came back negative. I hAve been very moody and tired and have had cramps in my abdomin. I was just wondering even though the test came back negative could I still be pregnant?