I'm 23 and just recently got married. My period is 14 day late as of today, I've never been this late before. I've had light lower back pain and some light cramping for the past 5-6 days, other than that I've had no other signs of pregnancy. I took a HPT yesterday and it came back negative. Could I still be pregnant? Also, I'm a Division 1 track athlete (pole-vault) and am currently in full training...how much exercise is too much while pregnant?