How can I stop getting so nervous?

HI I'm kylie I'm 14 and I'm in 9th grade
For the past year when I've had to present things like papers, stories, current events, etc. I get really nervous like a really strong pain in my stomach and I can't control it. I've tried taking deep breaths that don't help, I've told myself everything will be okay. I get home from school and then I'm fine and I don't worry about anything. is there something wrong here that I need to be worried about. and could I get an ulser from this?

http://www.helpguide.org/mental/panic_disorder_anxiety_attack_symptom_treatment.htm

It sounds like you may be having anxiety/panic attacks. Checkout the site and see if this fits you. Let us know if you have any more questions or if you don't think this applies.

the same thing happens to me!!!

You could be having anxiety, which seems what you are saying quite right. Try and relax more Yoga and aeobics will do you good ! you will feel much more relaxed!
Hope this helped --x
Bye!