For me, it started as feeling like a common cold, then very rapidly got worse, nothing over the counter or doctor prescribed was curing it. I had: extreme sore throat, dangerously high fevers, flu-like symptoms (vomiting, chills, weakness, aches, etc), blood clot in juggular, blood clots in lungs, fluid in lungs, collapsed lungs, sepsis, malnutrition (from being unable to eat for weeks).