Just got laid off, what should I do first? after 11 years as a social media manager

They called a meeting on Monday and 11 of us were let go. I had been there 11 years. I worked as a social media manager before this. 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 last year, and it settled down once I kept a simple log of every call and form.