Just eat more, sleep more, think about it over and over, and attempt it in 2 weeks when your fresh and SMASH IT! Physically look at it anyway you want, its mental. If you were in another atmosphere the screams of brothers of iron would have made you lock it out.
I am currently working on a dead lift tutorial/FAQS etc.. and am gonna see if Ehubbs will help me since he is a raw 700+ puller to give it more credibility lol.
But honestly don't overthink it, just grip and rip. SFW!
Technical wise I would say keep your leg stance the same if thats where your comfortable, but push your knees out as if you were squatting to engage your legs on the bottom of the lift but let the hips come through since as you lock they will go back in position.