oh nooooooooooooo!!!!!
I get many sinus infections too and my colds last long time and I still have my splee...
If you don't feel icky about squirting stuff up your nose that comes out the other way, I swear by Ayr Saline rinse which you can find at most pharmacies. Be careful to blow your nose gently though so you don't push the infection into your ears. You want to buy the actual wash kit and not the spray. You pour warm water in and a saline packet and push the bottle. It squirts water up your nose which comes out the other nostril (i love body physics).
It has saved my life, especially flying with sinus problems which really sucks.
I hope you kick this infection soon!