Just got laid off, what should I do first? - 5 months and counting

I was let go as a procurement assistant this week and I am still in shock. It has been weighing on me all week. I have a box of my things and a short letter about benefits. Is there a checklist I should follow?

Thanks for writing this out. I went through something close to it 5 months ago, and it settled down once I kept a simple log of every call and form.