Your W-2 for tax year 2019 will include all of your wages for 2019 plus any severance pay received in 2019. You enter the W-2 on your tax return as received. You employer has until January 31, 2020 to provide you the W-2 for 2019.
You don't report or claim being laid off on your return. You just report the actual income you got. They should send you a W2 by Jan 31. It will probably include the severance pay, you only report the W2.