A neti pot is basically a sinus irrigator or rinse. You essemtially pour warm salt water through one nostril (while leaning over a sink or in the shower) and it comes out the other. It helps clear your sinuses of congestion and irritants.

As for allergey meds, antihistamines do nothing but make me sleepy. They certainly do nothing for my allegries. So, I wouldn't assume much from the fact that they didn't help you.

That said; Tulip is right. It's time to tale a step back and approach the problem with a fresh perspective. Good luck!