Severance agreement arrived, need a second opinion after 6 years as a warehouse supervisor

I was offered 6 weeks of severance after 6 years as a warehouse supervisor, and I have a few days to sign. It has been a long 25 weeks. I do not want to leave money on the table. Did anyone negotiate and succeed?

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.

Ask for the offer in writing and do not sign on the spot. A day or two to think is normal.