Tongue Weight (getting sucked in by trucks)

I had a Mazda Tribute (Escape clone) for a while and tried towing a small trailer with it. It did not do well. Side winds,trucks passing etc. all effected it. Not dangerously but it puled the Tribute around a little. Considering I had pulled the same trailer from Minnesota to Colorado and back twice with a Jeep Cherokee with no problems I was surprised by the way the Tribute was effected. Considering the Tribute and Jeep wheelbase were similar and on paper close to the same weight it seemed odd to me the difference in towing. Maybe difference in rear springs? Beyond towing the Tribute was a nice to drive SUV. Quick acceleration, Ok gas mileage, with a smoother and quieter ride than the Cherokee, but then what isn't smoother and quieter than a Cherokee. One simple thing to try to see if it is a trailer weight issue is empty your trailer, empty all waste and water tanks, etc. then take for a 30-40 mile round trip. Then fill it back up and take it over the same 30-40 mile route. If there is a noticeable change it may be a weight or balance issue. If there is no noticeable change then I would look at the Escape, tires, WDH adjustment. Look for the simple answer first.