2002 Cadillac Deville Suspension vert hard ride in winter

Suspension problem
2002 Cadillac Deville V8 Front Wheel Drive Automatic 61.000 miles

I live in minnesota and this winter the ride in my caddy is very hard and rough. Something not noticed last year. When driving on the freeway and driving over a section road joint it feels like the whole car gets jolted and city streets it's almost unbearable and most embarrassing with company in the car as this is a CADILLAC.I am told it's and FE! Suspension but not sure what that is? Likely not an air suspension I am also told. So, what gives? Any ideas?
Dave