Obviously more truck is always preferable...however I don't think you're overloading your truck. IMO you just have the wrong hitch setup.
I have a Grey Wolf 26DBH (31ft long, 7700lbs GMVW) and tow it with a 1/2 Ton Ram, but I have a Equal-I-zer 4pt 10k. i also added air bags because the Ram has an extreme squat in the suspension. It would squat bigtime, even with our old camper with a 4,000lb weight. The only white knuckle moments I've ever had were with 40+MPH cross winds on a trip last August. Other than that, I've towed 5,000 miles through just about every condition except snow and been fine. Once you get the hitch set up properly, I think you'll be A-Ok!
2016 Grey Wolf 26DBH following a 2014 RAM 1500 Outdoorsman
Life is good...Live it!
(2014) Nights Camped - 16 in 6 trips (2015) Nights Camped - 20 in 6 trips
(2016) Nights Camped - 21 in 7 trips
(2017) at least 23 Nights Planned in at least 6 trips!