Just a few tips:
Know your season. Hay fever is usually caused by an allergy to a specific "alergen," so some people suffer in May (Trees) and others in June (Rye grass) others in July (Wheat). Know your enemy (allergen).
Symptoms are made worse by pollen sticking to various parts of the body, hence;
Rinse eyes with cold water frequently,
Dab vaseline around the nostrils (no seriously), to stop pollen entering nose,
Drink fluids regularly to avoid itchy palate.
(Pollen is harmless when it reaches the stomach.)
There are some topical medicines available which can help with symptoms (nose sprays / eye drops.) These are available over the counter, and shouldn't cause too many side effects, especially tiredeness.
However, check with your doc, as I am only a PPL student, who can't even fly that straight. (or level).