It seems odd that speed would have bent it, but yet possible. I haven't had an issues with my 5er antenna, but the power radio antenna on my vette has a slight bent to it that wasn't there originally, I know I have never hit the antenna with anything, so it must just be the wind. I have brought the car up to over 140mph (traveling speed, no wind), so I imagine there is some force against that thin aluminum.
Did you possibly bring the trailer up that high? 70mph ground speed, 70mph head wind?