Just took a look at Craigslist Seattle and for $180 there are/is several WDH's with sway dampener @ $100 AND brake controller at $80. Also I didn't see if anyone asked if your trailer is level when towing. You will need most likely a drop hitch to level.
Good luck and take some of the criticism with a grain of salt after all at 70 years old most of the knowledge was infused at birth and not learned by experience.
LEN
Had a second thought, do you have a frame mount hitch on the truck or just a bumper hitch? The frame mount 2"x 2" is what you need and again Craigslist is a good source.