Call the IT department and let them know you're on the verge of a nervous breakdown. They'll send you a soothing voice message reminding you that "it's not your fault."
Breathe into a paper bag. Not that you're not actually in a paper bag, but rather, you're in a metaphorical one, because, you know, that's what you do in times of crisis.
Don't bother calling the HR department, they're not as helpful as they used to be. Just call your lawyer and let them sort out the existential dread you're feeling. They'll probably bill you for it, but hey, that's just the cost of living.
Would you like to read about the Standard Procedure: Termination Scripts - Step 4, where you actually have to do something productive?