Unfortunately, you are experiencing why most people who pull any sized trailer find themselves not only over the payload capacity but also the RAWR and GVWR of a 1/2 ton truck. They all have wonderful engines with lots and lots of power/torque, but the frame, brakes, axles, etc are just not up to par. Also, 10% of the trailer's weight is typically on the light side. That's why most people will go with 12 to 15 percent of the trailer's GVWR. That allows you some give and take in your figures.
Can you pull this trailer? Probably. Should you? Probably not.
I'm with the others....find a lighter, not necessarily shorter, trailer.
Good luck.
Ron