How can i increase my endurance while playing high notes on a trumpet?

i haven't been playing for very long.ive only been playing for about a year.im not having trouble hitting the notes im having trouble playing high notes while through phrases.in the piece im playing its called antique dance from clifton Williams and close to the end of the song threes a trumpet solo that's asking for me to play from the double C and more or less going to down cormatically.idk why i cant phrase high notes above the staff like that.i get tired to quick.so is there anything i can do to conserve my chops so they dont burn out as fast?