If she's a true friend, she'll tell you the same things we've been saying to you; your truck is too small for that trailer.
Even empty, your trailer is too large and weighs too much for that truck. The idea of you pulling it loaded gives me the heebie-jeebies.
I pull my trailer loaded at 60 mph. And haven't had a problem, but my rig is designed to go together and there aren't any sway, stopping, or load issues.
I won't get into tire pressure for both vehicles, proper maintenance, and brake boxes, because they're irrelevant to this situation. The truck is too small for the trailer and nothing is going to change that.