Laid off this week, where do I start?, accounts payable clerk here

They called a meeting on Monday and 16 of us were let go. I had been there 16 years. There are 16 people counting on me, so I am trying to be careful. I have a box of my things and a short letter about benefits. Which steps were urgent?

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.