Budgeting tips when income drops - any advice?

My income is now a fraction of what it was as a retail manager and I am trying to cover the essentials. I have been trying to stay organised about it. 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 4 months ago, and it got easier once I kept a simple log of every call and form.