Do you have a single or dual axle now? How far forward from the back of the boat is the axle or the center of the two? Are your tires properly inflated? What are you towing it with?
My Donzi I can pick up the tounge with my fingure. It trailers perfectly. My hydrostream was the same way. You may have a allignment issue with the axles also. Make sure they are perfectly parallell to one another and straite on the trailer.