Allergies worsen in someone's 20s and 30s!! They actually go away somewhat, sometime after that age period.
I have severe allergies - and at times I have FELT flushed, chilled and feverish..but I really wasn't feverish at all. It just felt that way.
though if you really do have a fever..I'd get it checked out. I do wonder why they call it "hay FEVER"