You can buy 'sports strips' from any chemist. Rugby players and similar use them - they are small velcro strips which you placce across the bridge of your nose. They keep your nostrils slightly more open than normal, to allow additional airflow, and should sort out your problem.
Yes, but these strips don't always work! I bought some for my husband hoping it might cure his snoring, it didn't & he woke up in the morning with it stuck to his ear'ole!