hi all i am a type one teenaged diabetic in need of some assistance.

ok so yesterday at lunch, i went to subway and ate there without my insulin, about 5 minutes from home. i started eating and then when i got home, i completely forgot to take my insulin, so at dinner at 7:15, i had a 543 blood sugar. im kinda freaked out right now because i have a race tomorrow (i run cross country for my high school) and ive never been that high before. ive been diabetic for 10 years and i was just wondering for my biggest slipup i can remember in the years ive been diabetic, what are the negative effects of my mistake? i took a lot of insulin to correct it but will my race suffer tomorrow? is there anything else that will happen? i experienced no symptoms before checking it by the way. A sooner response would be best. thank you very much.