You need to weigh your truck, separately (not connected to trailer). You can weigh it empty, or loaded up, to include you sitting in it. Either way, plan on the same configuration with trailer hooked up.
In otherwords, weigh the truck, with front axle on the first scale, rear axle on the second, full tank of gas, you sitting in cab. Get that weight.
Hook up trailer, with weight distribution fully connected, with you in the truck, full tank of gas (again), same config as stand alone. Front axles on one scale, rear axle of truck on second scale, trailer axles on third scale.
Subtract weight of truck weighed alone (both axles), from weight of both axles when connected up. Difference should be your tongue weight.
Now there are folks who will disconnect the WD hitch so you get deadweight hitch weight, and distributed weight values. I can see the value in doing that, but I haven't done that. I get three weights.. Truck alone, truck with trailer dry (empty), and then truck with trailer fully loaeded ready to go. I just like the dry weight vs loaded weight so I know how much cargo I have in the trailer.
If you plan on loading a fair amount of stuff in the bed of your truck, I would weigh the truck fully loaded as if you were heading out camping.
The problem with how you did it, if I understand what you did correctly, is you have no idea what your truck alone weight is (without trailer). You need that value as a baseline to start with, in order to understand what weight is added as a result of the trailer, and how it is actually disributed. Knowing individual truck axle weights (stand alone), you will be able to see exactly how much weight is distributed to each axle by the WD hitch.
Mike