What George said. Aim for a better posture from the start (think: big chest, arched back) and a consistent back angle as you pull from the floor. Your hips are rising too fast relative to everything else and you end up being slouched over the bar.
As for the 2nd pull, I think what's holding you back the most at this moment is that you're using too much back extension and under-utilizing your legs and hips.
Check out the slow motion portions of this vid and notice how the back angle stays constant off the floor, the knees re-bend when the bar gets above knee level, and the aggressive extension of the legs and hips.
Fix your positioning from the floor to your 2nd pull and get more lower-body involvement in the lift and I have no doubt you'll be good for a lot more.