Do you have a rescue inhaler? Using a rescue inhaler regularly, about every 3 - 5- hours will help open the airways so that the mucus can be expelled more easily. You are taking an expectorant (guaifenesen (Mucinex)). Pseudofed may be helpful, but it keeps me awake. Lots and lots of water would be beneficial. The Advair will help with the congstion in time as inflamation causes mucus production. It might take a while for the steroid in it to start working though.
Other than the rescue inhaler, it looks like you are doing everything possible to avoid the secondary bacterial infection.
Feel better.
It will take a while for the mucus to settle down, just give it time. Keep using the guiafenasen and advair, make sure you are drinking enough water and resting.
If it's not any better in another week, you should talk to your doctor again and make sure that you don't need a short dose of prednisone.
Are you using a peak flow? You might want to use if your peak flows are still low or back to normal and its only the mucus that is making you tight.
If you have a virus an antibiotic wont help. Antibiotics will only kill bacterial infections. I would try a stronger decongestant like Sudaffed that is behind the counter. If you have a tight chest you should also use an expectorant. Resting to keep up your energy and a lot, I mean a lot of water will break up the mucous and flush your system. Advair will reduce inflammation of the bronchial tubes but wont help with the mucous. Good Luck, hope you feel better soon!