Use DoTērra Essential Oils. Every 2-3 hours throughout the day mix one drop each of peppermint, melaleuca, and an essential oil blend called Breathe and rubbed the mixture all over my sinus area – forehead, temples, nose and outward toward cheekbone.
If you're one for taking medicines, Mucinex (not D, not DM, but plain) worked wonders for me in my 2nd trimester.