sore throat

I had a bad cold last week that began with a sore throat, and the cold symptoms all cleared but the sore throat came back even worse. I can barely swallow and I wake up in the middle of the night in coughing fits. I can barely eat because it hurts to swallow. I've tried Advil, honey, tea, gargling with salt water... everything I can think of and nothing will work. I went to the doctor and they were very dismissive after a steep test came back negative. What do I do now