What Causes Chronic Nausea, Headache And Joint Pains?

Hi, my husband has what we thought was flu, he has been unwell for 2 weeks now, he has nausea, he has been vomiting, headaches, aching joints, seems cold all the time, an extremely painful wrist, which the doc thinks is tendonitis, diarrhea and now how a pain in the right side of his groin. I am getting quite worried about him as he is never unwell. Thanks