Heyla! I'm so sorry mama!
I just got over a THREE WEEK cold of viral doom (it was horrid) and spent about two weeks of that coughing insanely. And this late in pregnancy it was a whole new world of "not fun".
On the "holistic/natural" front:
--You want to change the ph and temperature of the throat to help clear things out. This can help with both coughing and throat pain. So hot water with lemon & honey or herbal teas like Herba Tussin or Throat Coat (both by Traditional Medicinals and both cleared by my OB and midwife). Fruit juices like orange and cranberry are also good.
--if you eat meat, chicken broth is a classic and has actually been shown to help in clinical trials! If you're veggie then any broth will do, but try to make it a little saltier and a little fattier than you would otherwise.
--Gargle with salt water (again to soothe the throat tissues that the coughing can inflame)
--get a pot of really hot water, add a little eucalyptus or tea tree or other really head-clearing oil, drape a towel over you and the bowl and breath the steam for a while. You can also do this in a really steamy shower with one of those "shower cold care" products they sell at grocery stores (a little scented pellet you put on the floor of the shower).
--sit or sleep near a humidifier that also has a vaporizer so you can freshen the air with a head-clearing/lung-clearing scent while the humidity helps break up congestion and soothe your throat.
--I made popsicles (using a freezer popsicle mold) out of a little plain yogurt, some fruit juice, and some water. It's true the dairy product can make mucus worse, but I found the soothing cold to be a huge help...especially at 3am when I couldn't sleep due to coughing! I also made some popsicles out of the herbal teas I mentioned, but while this was refreshing it wasn't as soothing.
--anything with guafenisin (though most OBs will tell you to avoid things with dextromethorphan...the "DM"....so I'm sort of surprised that the pp's doc okayed that!) will help with congestion and coughing. Double check with your care provider though just to be safe. The one my care providers prefer is the Robitussin (not DM) version, but there are plenty of generics out there.
--cepocol throat lozenges...they numb the throat a little and can help if the coughing is being set off by a throat "tickle"
--actifed, sudafed, and benadryl are generally okay (though ask for the "real" version behind the counter...not the "new" version available in the aisle) and good if the cough is being triggered by gunk running down your throat. The meds will dry up the gunk and clear nasal/head congestion which might help with the coughing.
I hope you feel better soon...being sick while pregnant is just awful!