Why are my brakes supplying themselves as I drive?

When I start driving my 2000 f350 automatic 7.3l diesel, I’ll get to around 6 km of driving and then the brakes will start applying, applying more and more pressure as I drive until the vehicle almost shutters and then suddenly just breaks free and drives normal again.

At the same time the brake pedal will be hard as a rock, just tapping it applies a brakes even more.

What is causing this?