I Have been getting nasty hayfevr all my life too and I have found that FESS works really well. Also a girl at work put me onto a product that you get at health food stores called 'Tissue Salts' they cover a range of ailments and I have been using the one for hayfever. It is not a cure, but now I only need to blow my nose once or twice a night instead of 11or 12 times per night.
Also do not ever, ever, ever settle for a hotel room that has been smoked in.