Shaking in steering

I have a 2007 Kia Rondo v6. It is shaking violently in the steering wheel at speeds of 45 to 75mph and at speeds of 45 to 50 if you let off the gas it will settle down some. Also if you go over 75 or 80mph it barley even shakes. We did new rotors and brakes and it still does it and it is getting much worse and it is getting more difficult to drive. I was told today by someone it may be my CV axles. Now about a month ago a tractor trail had a blowout in front of me on the interstate and I was unable to mess the retread that went under my left front tire and it sound and felt terrible when I hit it. COuld that have damaged my tie rod and bent it? What does my husband need to check? Or is this a steering column problem? I am about to go crazy and is this dangerous for me to be driving also? Thank you.