Budgeting tips when income drops - any advice?

My income is now a fraction of what it was as an operations analyst and I am trying to cover the essentials. This is my first time dealing with any of this. The rent is fixed and the car payment is high. Any apps or methods?

Thanks for writing this out. I went through something close to it 12 months ago, and it got easier once I kept a simple log of every call and form.