The lady wanted to go to the gym so I tagged along. I'm sure this was in no way a horrible decision and won't have any ill effects on my bench tomorrow
You're not getting any tension from your feet through to your upper body. Back injury precluding some more arch? Maybe try to get more of your weight up on to your traps? Feet back closer to your head might also help.
Did that thing you see Instagram girls do where they start behind the bar and contort themselves. It worked ok I think, although I can only keep my toes on the ground