Advice

So I’m 14 And I know I really don’t supposed to have stress But i do And It’s getting Worse and worse Everyday I worry a lot , Some Of My Hair is Turning Gray And I get a lot of headaches . So I took this test to get into a good high school but I didn’t get the score I needed so I failed and I jus feel so stupid All my friends got in there schools that they took a test for and I’m happy for them and I’m just so worried about 8th grade It’s literally Stressing me out i don’t know what to do any advice ?