welcome to the club, start taking antihistamines immediately because they take a few days to build up in your system. If after a a week it doesn't seem to be helping try changing to a different one, cetirizine, loratadine etc. I find Beconase nasal spray works well if the symtoms are getting worse.
This is a new thing for me... eyes stinging and running, nose snotty, stupid itchy cough... sounds like the fever of the hay?