Appendicitis or paranoia?

Right now it is Sunday night for me. yesterday, Saturday morning to be exact, I felt sharp pains in my abdomen and they lasted for about an hour. To be specific, the pains felt like something inside of me was stabbing the inside of my stomach. I honestly just thought that this was gas. The pain subsided and i didn't get it back all day. Well today, sunday afternoon, i became VERY nauseous and this lasted for a few hours. I've never gone that long of being nauseous without ACTUALLY throwing up. I then got the abdomen pains back and those last for an hour. The nausea went away. I had diarrhea too. About an hour and a half ago i got the sharp abdomen pains back and they hurt so bad that i had to bend over and hold my stomach. They were only poking at one part of my stomach though and it seemed to be around my navel. well half an hour ago, the nausea came back and i finally vomited. Sorry to be really specific here, but each time the vomit came out (about 3 gags) it was a LOT of water with the food. The abdominal pain left but there is discomfort in my stomach. I'm 15 years old by the way. I don't know if i should be worried or not. My cousin died a couple years ago from appendicitis and he was only 4 :(.