'08 Fusion shaking and vibrating, almost bouncing

OK, so here is the deal. I have 20,000 miles on my Fusion 4-banger. All of a sudden, when I left work today, it began shaking as I reached about 25 mph. It feels as though it is b/w a shake, vibrate, bounce and jerk, almost like when you shift up too soon in a manual, or don't downshift soon enough. The shaking is throughout the whole car, I can feel it even in my legs. So far, I have only been able to go up to about 62 mph, and it doesn't go away. It is idling at about 500 rpm, and gets up to 2000 at 62. Don't know if it matters, but snowed a few inches today and it was slick on the road, so I spun going up a hill in the morning. I would greatly appreciate any insight as I am nervous as a you-know-what to drive it. Any safety issues? Thanks in advance for your help.

Check for ice/snow build-up in on of the wheel rims. Can throw it WAY out of balance. Good luck and let us know how it turns out.