Severance Package

So.. I'm on maternity leave and it ends tomorrow (Dec 14). My employer informed me a few weeks ago that they're laying me off due to shortage of work and downsizing. They've offered me a severance package of 16 weeks in wages plus 4 weeks of holiday pay. I've been with the company since 2013 and have gone on mat leave twice. They said that I don't need to sign anything and that they're just sending me a letter to make it official. I'm 32f. What are your thoughts?