So i'm in the 10th grade and all my life i've had 20/20 vision, it was the same at the beginning of this school year, but now, i can barely read things written on the board in school. i'm worried about my vision. anybody know any possible reason this could be happening? Also, i had been told multiple times i had a thyroid problem so i searched the symptoms and have almost EVERY single symptom, yet my doctor still won't believe its a thyroid problem, even though the first blood test came back positive. what should i do? thanks!