If it’s in the US you have protections from radical changes to your schedule or shifts.
Depending upon the laws of your State you could refuse, force them to fire you and then collect Unemployment benefits while you search for a new job.
While you’re collecting you could get an attorney and sue for unlawful termination.
Don’t take it lying down.
That’s what they’re hoping for.
Find out your rights, and use any vacation or sick time until you know them.