Hi there,   I hear you! I've had this exact experience... many times. And I can rarely explain it. For instance, I go to the same restaurant every Friday evening. Most of the time, I don't have allergy symptoms while I'm there. But a few times, I've experienced itchy, watery eyes, itchy mouth/throat and wheezing and coughing almost the minute I walk in. I have no clue what's been different on those occasions.   But your body is definitely having a reaction to something. It might be that there is some new kind of tree pollen in the air (or an especially high level of it). Or it could be that you came into contact with something else in your environment that triggered your symptoms.   Allergies are rather unpredictable at times. Keeping a detailed symptom diary may help. But in all likelihood, you will never know for sure. I'm sorry to tell you that, but that's been my experience.   To your health, Kathi