how can i not be so out of breath and tired while running?

So i do track and field and i am a jumper but im really good at it and my head coach wants me to do the heptathlon. The only problem is i have pretty bad asthma and there is an 800 in the hep. That means i have to sprint two full laps around the track and i always am horrible at it and i feel like im letting my coach down and can't live up the potential he thinks i have. I always take my en0-hailer before i run and it helps a little but i still do horrible and am out of breath. Literally. I am in pretty good shape so i shouldn't be doing as bad as i am. Any tips on how to not get so out of breath or breathing exercises to do while im running? Anything helps! Thank you!! i am a 15 year old girl by the way