Getting let go mid-year

I worked at a private school. Parents complained that their kids were not understanding the content and I was put on a PIP shortly after my second year at the school began. The PIP focused on the quality of my teaching (with really high benchmarks/expectations) and classroom management. While I passed the classroom management section, the principal did not feel the quality of my teaching had improved sufficiently enough. I was then let go mid-year. The school I worked at doesn't have a union and the principal declined to give me a letter of recommendation.

I really want to go back into public school after this but I'm worried I might not get hired. After all, I've only stayed one year at every school due to nonrenewals. I've considered changing careers / substitute teaching but I don't know what I could do. Any advice would be appreciated.

EDIT: I taught math in middle school. Nonrenewals from other schools were mostly due to classroom management + reduction in force.