Filed Taxes for 2019

I’m recently divorced as of August 20th 2020. I had to file my 2019 taxes as married filing separate and I did so. I was the only one working while I put my husband (ex husband now) through nursing school. I showed all my 2019 bank statements and his school form and I only made a little over $20k and I have never owed taxes and something must be wrong with my tax return. What can I do?