Welcome to HCM. Gastro can be caused by bacteria or viruses . The problem with being nauseous all the time is that you can struggle to rehydrate orally . For that reason it is often better to receive intra-venous therapy. Not only fluids are needed but also electrolytes and probiotics or antibiotics. Please consult your doctor because electrolyte imbalance has the potential to be life threatening. I trust you get well soon.