There are actually tons of reasons why you might suffer from these late-onset seasonal allergies, even if you've never had a problem with them before. Sometimes stress causes our body to deplete its stores of vitamin C — leaving our immune system vulnerable.
Allergic reactions can also often affect our guts, leading to sluggishness and even depression. Ultimately, consider getting a professional allergy test if you've got a cold that you just can't seem to shake — it could be something else entirely. (MindBodyGreen)