Hi. Welcome to the forum. Also, pregnancy is not an emergency so 'HELP!! " is really not appropriate and should have been thought of more in the 'prevention' stage.
First and foremost, when in doubt -
Always see your doctor.
Second, Take a EPT or HPT, even though they might be negative does not mean your not.
http://www.babyfit.com/register.asp
Check out the following sites, they will help you through this a little more to reassure if you are.
http://www.mayoclinic.com/health/sym...gnancy/PR00102 scroll down and even get answers on flying while pregnant, exercise, dangers, etc.
http://www.epigee.org/pregnancy/symptoms.html
www.askdramy.com The U.K. online doctor.you can post on a forum, or 'ask the Dr. Amy' with a click. The FAQ Tab on the homepage is also a good place to click and has a lot of good subject matter. P.S. Most of the articles are printable in PDF format.
Good luck, and keep us posted - and remember, these sites
do not take the place of a doctor's visit!

Safety and prevention is far better than panic and pregnancy if you're too young to take the responsibility.