Hello ma'am, congratulations on your pregnancy :)!
I'm sorry to read about your troubles though!
Although some ingredients found in syrups are considered safe during pregnancy, they are not recommended, mainly because of their ineffectiveness. In fact, they have not been shown to be any more effective than drinking lots of fluids or even a teaspoon of honey.
The best treatment remains nasal hygiene with saline solution such as Hydrasense or Sinus Rinse, which can be done as often as necessary during the day and at least 30 minutes before bedtime. It's a little uncomfortable but works extremely well to prevent secretions from running down the throat, which often causes coughing.
I encourage you to drink plenty of fluids, cold or hot depending on your preference.
If you have pain (throat or otherwise), Tylenol can be taken without problem, as well as lozenges like Halls or Fisherman's Friend for local relief of throat irritation.
Some decongestant nasal sprays can be used for a short period of time during pregnancy, depending on the active ingredient, I suggest confirming with your pharmacist.
I hope I have been helpful to you and I am available if you have any further questions!
Sincerely,
Tom Samaha, pharmacist