I Have Been Very Nauseated , Belching Constantly, Bad Headache

I have been very nauseated , belching constantly, bad headache that won't leave, feel hot and cold at the same time. I have had stomach viruses , flu ect before. Do not believe it to be either. I had some temporary caps in my mouth that became very infected and were removed today. horrific smell. I am worried about being poisioned from them. I know of a case like this where someone younger and healthier than me died 2 years ago from same thing.