Don't count on a dealer to do it right. They usually do not take the time necessary or have techs that know how to properly set it up for each individual rig. They usually can install it ok, but forget about the 2nd step which is adjusting it properly.
Take a look at
this thread for some help on doing it yourself. By doing it yourself, you not only are sure to get it right but you learn a lot about your hitch in the process.:) It is not hard and just takes a bit of time and care.
You have a small trailer but many toy haulers have very high tongue weights until the "toys" are put in the back. By your description, you probably did not have enough weight transferred back to the front of your truck. That thread I linked to will help you get your hitch set up correctly. Good luck.:)
Barney