I have been congested this whole pregnancy. I have always had sinus problems and it is freaking miserable. My husband is making me drink apple cider vinegar and honey in warm water before bed to clear them out so I can sleep. It is not the tastiest tonic but when desperation sets in, I would do anything to sleep. I am 41 weeks now and seriously need rest. I'm averaging 4-5 hours of sleep a night which my midwives are not happy about (that has been going on for 2 months now. There really is no way for me to not go into labor sleep deprived at this point.). With the tonic (and my dislocated rib finally healing), I am able to sleep more like 6 hours a night and it is making a huge difference.
Sinus Congestion Tonic
8 oz warm water
2 tbsp apple cider vinegar
1+ tbsp honey (to taste)
Mix together and drink. Might burn a bit going down, but it will work.
Other that that, I am sleeping propped up on a ton of pillow and drinking hot tea like its going out of fashion. Sometimes a bready snack before bed also helps to slough off post nasal drainage. I eat saltines. Also, I can't use a netti pot because I can't tilt my head back due to a tonsillectomy without it just draining down my throat. I found a solution to that with the Nasopure. Its more like a squirt bottle for saline and works pretty well. I used it for a while, though I am "enjoying" the tonic more so lately.
Do keep in mind that the further you are along in your pregnancy the more likely the tonic will give you heartburn. A Tums or some kefir before can help, but avoid dairy after because it will just clog your nose again.
Good luck and I totally feel your pain.