Sadly at 57 you are highly unemployable so you need to examine your skillset gain through working for the government and how they apply to the private sector. Where your future may be is as a consultant/advocate to the private sector navigating the fiefdoms of government. Before you hang out the shingle you need to talk to a lawyer and find out how starting your own business will affect your severance as you will need the money until your business gains traction. You might find you need to talk to a lawyer about both the terms of severance and getting it converted to a lump sum payout. 

If self employment is not your thing apply for assistance and get retraining. Oddly a good thing to get is a level 1 first aid ticket, it is easy to get and not that costly. It is a desirable skill, depending upon where you are applying, that could make the difference. As for the whole you get severance but it is contingent on you making an effort to find work is unreasonable and should be banned.