Most likely when you lay down to go to sleep at night, even if your bed is slightly elevated, the mucous drips down the back of your throat and causes you to cough. Night time coughing, as you know, can be relentless. If after a week you still have any fever, I think it is time to see the doctor as you probably need an antibiotic to clear this up. Feeling better in the day is a good sign but a low grade fever is a sign that your body continues to fight this infection. And after a week, what may have started as a viral infection now certainly could be bacterial.
Sometimes, you can stop a night time cough with a medicine like Nyquil Cough. This contains an antihistamine to stop the drip and a cough suppressant. If this doesn't help, the doctor can prescribe a cough syrup that contains alittle bit of codeine and that will definitely stop it.
I hope you get better soon.
If you have further questions, don't hesitate to ask me.
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