Plant closing and notice period questions after 18 years as a project coordinator

My employer announced that the site will close and gave us written notice. There are 18 people counting on me, so I am trying to be careful. Some colleagues are already leaving. Has anyone been through this?

Keep everything in writing and save the confirmation numbers. It saved me later.

Thanks for writing this out. I went through something close to it 8 months ago, and it got easier once I kept a simple log of every call and form.