Wow, that sounds like a nightmare. I'm sorry. As someone who watched a major downsizing take place, if you'd asked me for advice, I would have said take the severance package. Working in the aftermath of something like that is generally not a positive thing. Being overloaded with additional responsibilites seems like the norm in those situations. But, I get the pressure you must have been under to stay if they really wanted you to.

Can you start looking for another job? That seems like the best option going forward.