Hi, thanks for your question, I'm sorry to read about your troubles!
Your best option is nasal hygiene with a saline solution (Hydrasense, Sinus Rinse and others), which can be done as often as needed during the day, and at least 30 minutes before bedtime
By 'cleaning' the nasal secretions, we can decrease their backward flow, which often causes congestion, discharge, and coughing. It's a little unpleasant but it works wonders! It is also one of the only solutions that is completely safe and compatible with your health condition.
I also suggest drinking plenty of fluids, cold or hot depending on your preference, and you can use lozenges to help provide local throat relief, like Halls, or Fisherman's Friend among others.
Finally, I strongly suggest you go to the following link, which is a self-assessment of your symptoms to assess the need for testing. I know, we're all tired of it, and I've been tested several times myself, but it's still one of the best ways to avoid complications, and protect those around you.
I hope I've been of some help to you, and don't hesitate to ask any questions you may have!
Tom Samaha, pharmacist