Severance and unemployment, do they overlap?

I was offered severance of 15 weeks after being let go as a logistics coordinator and I am unsure how it affects benefits. It has been weighing on me all week. 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 13 months ago, and it settled down once I kept a simple log of every call and form.