There's a nasal spray called "Otriven", it's a saline based spray that is safe during pregnancy. I was told to use it by my GP when i recently had a virus which blocked me right up too. It really helped me to be able to breathe normally.

You can take painkillers with codiene in them like Panadeine, just make sure no ibuprofen in it. Unfortunately we can't take any of the cold & flu products on the market while pregnant. Just make sure you keep your fluids intake up too.

Take care & i hope you feel better soon.