Truck advice for truck camper

If it is swaying at slow speeds, then the weight is too much for your leaf springs. Get an add-a-leaf or helper spring. Be prepared for it to ride hard unloaded. If it only does it while driving fast, then it is the wind. All you can do for that is get a deflector like big rigs have on the roof

Air bags level your truck. You have a sway bar and steering stabilizer on the front already.

I did airbags and upgraded shocks. That did the trick for me. Also make sure your tires are aired up all the way.