Seems you have the head tilted too far back.. Youll need to readjust that..
Getting the rear nof truck back to level is wrong. Your taking too much weight off and mostlikely adding weight to the front of the truck..
You must start off with wheel well measurements of the truck not kooked up.
Then you need to get the height of the tongue of the trailer leveled so you could set the ball height.
Take a washer out of the head to get the tilt up. ( How many you have in there now?)
Your only goal is to restore the front of your truck to original height. The other goal is to keep trailer level...
What this vid on how to set height..
https://www.youtube.com/watch?v=WTQ5ML-O4B0What this one on bar set up too..
https://www.youtube.com/watch?v=xqZ4WhQIG-0This is a good one to watch to get a general idea on leveling
https://www.youtube.com/watch?v=ymcB2yeZr4s