I used to get allergies really, really badly. To the point that when I was on three prescription drugs my teachers would still send me home!
I don't get them as bad anymore, thank goodness, but I have sympathy for those that do. Feel better soon!
What I used to do when they got bad was altnernately use a humidifier (or, when it was bad, I'd just hang my head with a towel over it as close as I could to a pot of boiling water!). To the point that it drenched my face and I felt like I was drowing! Then I'd start to feel like it was cleaning my nose out a little, and it would help. I'd use Vick's at the same time, just like with a cold. Then I'd use an ice pack on my swollen sinuses.
This works best when you have a cold, which is when I started doing it. But then when all those Rxs didn't help my allergies, I did the same thing, and it would give me a little relief. And when you're suffering that badly, even just a little helps!