What Causes Tiredness And Chills Along With Vomiting?

My 73 years old wife has been getting tired easily lately and this morning she says she is freezing cold despite that it is warm in the house. She has been vomiting and her temperature is 100.8 Fahrenheit. She recently had a kidney removed because of a cancerous growth but appears to be progressing well. She says she hurts all over but doesn t claim any specific area of pain but for the last few days she had complained of back pain. I suspect the flu but I am worried about a possible onset of heart attack even though she has no history of heart problems.