I filed my 2020 taxes not knowing about self-employed family and sickleave it’s December 11 should I amend my taxes now I didn’t know that was even an option

I am self-employed with a 15-year-old disabled child I did not claim the family and sickleave and my son was at a school for 19 months I lost most of my income and went on unemployment I need help amending my taxes what do I do with December 11 and I never got my first stimulus as well