HS kid,
I think you are a tough kid to come back on this thread knowing some trolls will take shots at you and knowing that you didn't have your best race.
Seriously, I think most HS kids would just avoid this thread but you didn't and you even took a couple shots back at posters so good for you.
As far as your last couple few races coming up (now this might sound weird) I have advice. Embrace the tension, the unknown, the drama. Enjoy the experience and the journey that you chose to take. You could have avoided all the stress of competitive running and just stayed home and played video games. But you didn't want that.
Push yourself to your limit but promise yourself that what ever time you run, you will not beat yourself up, don't look for excuses (which is a sly way of showing dissatisfaction with run and self) but as someone else said learn from the experience. Even "bad races" we learn from.
After all, you came back here took flak from the trolls so you must be a tough kid..