Got severance, how does it affect benefits? after 3 years as an insurance claims processor

I was offered severance of 3 weeks after being let go as an insurance claims processor and I am unsure how it affects benefits. I am in Phoenix, in case local advice matters. I have a mortgage and need to plan. How did your state treat it?

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.