Hi there! Sadly the nature of disease and course of disease is significantly unpredictable. But yes having a severity score zero means that disease is not able to do damage to your lungs. However this doesn't mean that you can roam around freely.In your scenario the best thing will be conservatively treating yourself and isolating at home with spo2 and temperature Monitering. For further information and guidance , consult.

It means you had a mild covid infection. You can stop self isolating 3weeks after onset of symptom. Best would be to get a negative antigen or RTPCR report.