Maybe it would help if you actually took the right medicine for your symptoms?
Nyquil has Acetaminophen, which might help a bit with headache and fever, but not as good as Ibuprofen for most people.
Nyquil has Dextromethorphan as cough suppressant, which may help reduce coughing a bit, but probably you need an expectorant to help clear out that crap.
Nyquil has Doxylamine succinate which is the ingredient that is supposed to make you drowsy, but, if you are still coughing and have a headache, is not going to do the trick.
Ibuprofen will reduce fevrer and headache better
Guaifenesin will loosen up the chest congestion, and vastly help with coughing.
Talk to a pharmacist! They will help you!