Hello,
there are moderate interactions between Nyquil( containing Nyquil) and Vicodin (containing hydrocodone). Using HYDROcodone together with doxylamine may increase side effects such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience some impairment in thinking and judgment. You should avoid or limit the use of alcohol while being treated with these medications. Also take the medicines at different intervals.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
This is a type of question that best left to be answered by a pharmacist. I think there are to many variables involved for this to be answered safely without knowing more about your medical background or history. All you need to due is call your pharmacist and they will be able to give you an answer.