Making savings last after losing my job

We are a household of 11 and need to cut costs quickly. I worked as a copywriter before this. Rent and the car are the biggest costs. What helped the most?

A simple budget with three columns, fixed, flexible and optional, made decisions faster.

Thanks for writing this out. I went through something close to it 2 months ago, and it settled down once I kept a simple log of every call and form.