It is only somewhat worse than typical flu, Heck lesser than Spanish Flu. Nowhere near plagues humanity weathered already. Much less terrible then wars too.
Tests have some 15% false positive rate and are not useful in a viruses that propagate this fast for any other intent than confirmation. They are getting improved.
Treatment is supportive, if you're afraid care will be overloaded, get a pulse oximeter, oxygen tanks, reduction and mask, disinfectants (esp. water treatment) and about month store of easily digestible, easy to prepare food, and certainly water to smooth over any interruptions. (Don't kid yourself, you cannot store a month of water. Maybe drinking water, but not technical. Still bulky.)
Multivitamin and extra vitamin C which maybe will help. (It is slightly effective in colds, which it is a kind of.)
If you're really rich, get some hydroquinone synthesized. Useful chemical even if you won't use it for this epidemic.
This, and quarantine, is the most anyone can do. Walking around in protective gear is a joke as operator error will kill effectiveness.