Could Pressure In Lower Abdomen And Spotting Be Due To Pregnancy?

hello, im 15 and sexually active. i am wondering if i am pregnant or not. i havent had a normal period since december 6th 2010 and think i concieved december 24th 2010 because i had abnormal spotting. i have gained 8 lbs and im always sick and throwing up and have all the symptoms. i feel alot of pressure in my lower abdomen too.it feels like a fish is swimming around. i thought i have been pregnant before but this feels way different. i just want to know if what im feeling is real before i get the test