From both of the pics you showed.. Your rig and the offending rig, I can see where the offending rig was going 35 mph, but they did not hit you square in the ass... Just glanced off your rear bumper and didn't hit your hitch at all..
Of course, that's just my opinion of just looking at 2 pics off the interweb and not seeing the vehicle myself.. :)
If the Chevy would have slammed you square on the rear... Yes, you would be in a lot more hurt than just the corner of your rig being hit..
Good luck!
Mitch