First, I'm sorry to hear that this is something you're facing. It's never easy, but I've found that waiting is often the hardest part.
Now is a good time to polish up your resume and make certain that you have contact information for colleagues and supervisors you would like to call on for your references. Good on you for being so well prepared financially. You're in good shape to weather the coming storm.
Your 401k will remain with the investment company that now holds it. You will have the opportunity to roll over your account to an IRA or leave it where it is. It's your choice.
As for your health insurance, it depends. You can continue coverage through COBRA or purchase your own. COBRA can be costly, so be sure to compare.
There's also the possibility of some coverage continuation as a part of a severance package. You'll have to wait and see on that count.
Good luck!