Let me start off by saying my allergies are awful.
I've had red eyes for 3 weeks and a nose that just will not stop. Several years ago, I found a Peppermint Spray from Origins that I would spray on my pillow at night to keep me breathing clear all night long. Recently, I found out I could make this at home and it works just as great.
Peppermint Oil (This is an essential oil you can find at health food stores $6-$8. A little goes a LONG way, it's a great investment, you'll use it for quite awhile.)
Directions: I picked up a small spray bottle in the travel size section of our local grocery store then simply filled it with water. After that, add about 10-15 drops of Peppermint Oil and shake it up. Spray on your pillow lightly (no need to soak it) before you go to bed. You can also spray it in the air for an air freshener as well. I LOVE THIS.
Seriously, I use it a lot and it really helps.