Hi Kimi -
Yep I have awful sinuses on and off (pregnancy related), I thought I had a cold that I just couldn't shake as my nose was continually blocked. I finally got some rhinocort which I used morning and night (2 sprays in each nostral) and it cleared up in a few days. Also have a look in the articles section of BB as I think there is an article on sinus pain in pregnancy and suggested remedies.
Goodluck with it - I know how painful and debilitating it can be.
NB- I wouldn't think the coughing would be related to sinus - maybe see a Dr re: this just to check if all is ok.