Laid off this week, where do I start? after 15 years as a warehouse supervisor

They called a meeting on Thursday and 15 of us were let go. I had been there 15 years. 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 7 months ago, and it settled down once I kept a simple log of every call and form.