Could this be a brain tumor?! Please help im a 13 year old girl :'(?

For the past week I've had a dull head ache that goes on and off. I feel like pressure in my head. I am nautious sometimes but it may be from the candy i like to eat :) I do tumbling and i had a terrible tummy ache right before class but once i started tumbling the nausea and head aches went away. I'm only dizzy when standing like 20% of the time and no blurred vision or anything. You don't think it could be a brain tumor do you? :( please answer I'm kinda worried if it continues for like another week Im gonna go to the doctor, thanks for any help :D btw i just got my first period last month and I'm expecting it on the 21 st i had headaches last period and they were similar to these, thanks again oh and since i was five I have been a vegetarian