Help!! Sports day tomorrow! 800m, High jump and relay!?

[Hippie.]

Oh no! I've got sports day tomorrow and i'm so worried! All the people i'm competing against are WAY better than me! First i have 800m which i'm rubbish at! Any tips? Please!! Then i have high jump! i really can't do it. we had a practice session today and everyone else was so much better than me! And i tried doing the fosbury flop but i landed on the pole! I can kinda do it with the scissor kick but not very high (only to 1.05m!) Please help! I'm not to worried about the relay. I'm quite competitive and i hate losing! I try my best but i'm so competitive i do rubbish! HELP!! xxxxxxxx