If you run almost everyday, then you will get use to it. I have P.E. since I was in kindergarten and now since I'm older I have to run a mile each Friday.
JOIN YOUR SCHOOL'S CROSS COUNTRY TEAM! You'll be running A LOT everyday. I promise you you'll get stronger, healthier, and running will be easy!
As you keep running, your body will build up resistance allowing you to run faster and longer. Keep going! Its gets easier, promise.