Question 2000 tacoma prerunner issues

[MILINIAC]

I have had little to no issues with my baby until yesterday. I was on the freeway with a full load in the bed and the cab full. I noticed when my truck hit about 70 mph on some smooth surface, the truck would sway from one side to the other as if someone was standing on both sides of my truck pushing from one side to the other (kinda like a boat in water). It has about 147,000 on it right now. I have new shocks ready to go on it. Is that the problem or is there something simple I'm missing?

Used to be an apprentice at a shop so I'm not new to working on things, but never encountered this. Can anyone help? Thanks.

[Lymerock]

could be as simple as an unbalanced load
also your shocks are prob ready for replacement if you havent done that yet which would combat that swaying to a degree.