No, it's not you. I had the same problem. The rig wandered all over the highway if there were ruts in the asphalt from semis. I had white knuckles, palpitations, frequently turned the air blue and arrived at my destination stressed and exhausted. Your friends probably didn't notice because they drove it on nice city roads. Yes?
I did some research and installed a piece of equipment called the
Steer-Safe. It's a product that uses big honkin' steel springs to keep your front tires pointing straight and gets rid of the "wander." You can turn just fine, but if you let go of the wheel, they will return to the straight position.
I got mine installed (with new Bilsteins all around) at Camping World. Been a happy driver ever since.