Should viruses and bacterial infections actually be treated right away, or let the body fight it a few days?

Depends. Some viruses like mono you let run its course. It is milder in little kids than adults, but there is really no rx other than comfort care. Others like Ebola usually kill you regardless. Strep can feel better in a few days, but come back a month later with deadly rheumatic fever. Some bacteria like pneumococcus or meningococcus can kill you in a few days if treatment is not started quickly.
Natural Approach. The body has some amazing tools to fight infections and often we "muck" it up by trying to handle it with other meds. Let the body fight it, if you can stand the symptoms.