My son had a virus that started on Christmas Eve with similar symptoms. Nausea, diarrhea, vertigo, double vision, fever, chills, body aches, lethargy, headache, cough. We spent Christmas in the emergency room. They tested for flu, mono, meningitis, Lyme and all kinds of other things that came back negative. It was an unnamed viral infection, they said. Go home rest, blah blah blah. Tens day later (and many doctors/minor emergency clinics later) most symptoms persisted. In the meantime, he developed a deep, excruciating pain in his side. An abdominal scan showed gallstones/ inflammation. A week later, they took out his gallbladder. All symptoms still persisted. The gallbladder was healthy when they took it out. No stones, just mild inflammation.
A week after surgery his health was declining. I called a cardiologist friend because my son had developed shortness of breath anytime he tried to walk. He said meet me at the ER. They admitted him for a week and ran every test known to man. Started him on antibiotics and many other drugs. He was in very bad shape. He had a spinal tap and all kinds of scans, MRI's, etc. They could not tell us what this virus was that was plaguing him. This was the first week in February and Covid-19 was not reported in the US yet. There was no test for it and no one even mentioned it to us.
He still hasn't fully recovered. He had to withdraw from school because he couldn't walk or sit up and his vision was doubled. He has post viral syndrome and the virus itself caused fluid on the brain. Before the "mystery virus", he was a normal healthy 20-year old who worked out every day and walked 6-10 miles a day at school,
By the grace of God, he is slowly recovering now. It will be a long journey for him. We hope he will be fully recovered enough to return to school in the fall.
In my heart, I believe he had Covid-19. The more we learn about the symptoms now, the more I believe it to be true. Someday there will be a test for antibodies and I will have him tested.