You don't need a 13mm belt, and it's probably hurting your ability to control your back right now, which is pretty much non-existent. I suggest purchasing a 10mm belt, from Pioneer/General Leathercraft or Best Belts, and using that, ASAP.
Squat
Stance too wide, not deep enough, knees not held out, back and torso not set, still breathing in when you start to descend. None of these things individually is a train wreck and WAY off from where it should be, but collectively they add up to you having a lot of work to do. Start with this:
1. Narrow your stance about 2-3 inches at the heel, but keep your toe angle about the same.
2. Before/between each rep: take a big breath, stop to brace your torso, then descend. Bracing is what you'd do if someone was coming to punch you in the stomach and you couldn't block or dodge.
3. Sit down a couple inches deeper while holding your knees out
Deadlift - you're not setting your back here, at all. It looks like you have no control over it whatsoever, and are completely skipping Step 4 of the DL set-up. You need to squeeze your chest up so your back flattens out, pulling the slack out of the bar while doing so, before each rep.
Watching these two videos may be helpful:
Originally Posted by Michael Wolf
