Allergies can develop spontaneously, and the fact that you moved out of the high pollen count area to a lower one, and then moved back again could have triggered your immune system to behave somewhat more powerfully than strictly necessary. To take myself as an example: I used to live in a house with cats and cycled happily to and from work, straight through the open grass fields. When I moved out and got a place of my own, I did not get a cat; and the next year I was sniffling and suffering from itchy eyes every time I cycled through the fields. In fact, sometimes even returning to the house with the cats could trigger the response, even though I had been living with cats since birth. Skip forward a few years to 'now': you can set the clock on me getting itchy and burning eyes the first few warm and dry days immediately after the winter (when the first trees release pollen en masse), and then again in mid-June when the grass decides to pollute the atmosphere. Thankfully, it stays with these minor reactions.
While this story is quite anecdotal, I suspect that this sudden appearance of mild hay feaver is indeed related to certain changes in my life. And therefore I suspect yours are too. One suggestion is to get a few cats to make sure your immune system is continuously active and does not mind the extra dose of pollen (if it works, let me know ;-)), the other is to find medication containing sodium cromoglycate: I've found the eyedrops containing this compound to be a boon, and I know that at least in the Netherlands, a nose spray is available too. The big advantage is that it doesn't get you wired: although what it does precisely is not known it is thought to 'stabilise' certain cells in your body which produce the histamin you get puffy eyes and a runny nose from.
Good luck!
