HELP!

Youve all seen my new tires yesterday

i went from the 285/70/17’s to a 305/70/17 (32-34.5)
i figured there might be SOME difference in ride quality being that theres a bigger side wall with possibly more flex
but…

its almost unstable driving at speeds at more than 60 mph, if i switch lanes the truck tends to move as if i have a low back tire (the body almost fishtails and swerves from side to side)

i tried messing with the tire pressures and it worked slightly but it still isnt a stable ride.
i have 23000 on it so i dont think the shocks being the case.

ive never had tires this big before, but i cant imagine this being the norm or else no one would drive with tires bigger than 33’s

any suggestions ??