Good luck. PAY CLOSE ATTENTION to the exit meeting. You'll be hearing things that are really important, not only about severnce but also insurance if you get that thru your employer.
Take notes.
TAKE SAMPLES OF ANY/ALL WORK YOU'VE DONE.
Take business cards from sr mgrs who can attest to your wonderfulness in the workplace.
Take copies of your performane reviews that can attest to your wonderfulness in the workplace.
In the quiet of the next couple of days/weeks, take the time to use your e-mail etc to LET EVERY SINGLE PERSON YOU KNOW KNOW THAT YOU'RE LOOKING FOR WORK. Jobs often come thru the grapevine, not normal channels.
Check out any professional organization representing your career. Do they have an online job board? Networking opptys? Meet-n-greets? Sign up and get out there.
I am really sorry this has happened to you. With any luck, you won't be out of luck for long.