A clear issue is that you are really loose and you need to get much tighter.
This is most evident in your chest and shoulders. This comes from a poor setup.
Here's something you can try:
When you approach the bar, start with your feet just an inch or two within shoulder-width apart. Don't go crazy about this step, you'll figure out the proper foot width when you reach for the bar. You can point your toes out a bit or you can keep them pointing straight ahead.
Place the bar over the middle of your feet. You want the bar to be in the middle of entire foot, not just the portion that you can see. This should put the bar pretty close to your shins but it wouldn't be touching them.
Now that the bar is in the correct position relative to your body, stand back up.
While trying to keep your chest facing forward (not facing the ground), bend your knees so that your arms come straight down. Your arms will be just outside your knees. Again, don't bend so much at the hips -- you know you are bending at the hips if you back starts to move closer to parallel to the ground instead of being relatively perpendicular.
Because you keeping your chest facing forward, it is possible that are you are just barely getting to the bar. That's fine. If you need to face your chest downwards a bit, you can.
When your moving to the bar, the movement is similar to what a women in a short skirt looks like when they are picking something up -- they don't bend at the hips.
Once you get your hands on the bar, retract your shoulders pretty hard and get your chest and head up and facing forward. The retraction of your shoulders and the lifting of your head and chest will bring the bar to your shins. This is the step that creates tightness. It also puts your back in the proper position. To reiterate, you want you chest and head up and your shoulders retracted. You should feel uncomfortable. You should also feel the tension in your hamstrings.
If you don't feel the hamstring tension, you can try retracting your shoulders and puffing out your chest before you bend your knees to get to the bar.
Now that your chest is puffed out and your shoulders are retracted, you want to squeeze the bar as hard as you can. Really squeeze the shit out of it.
Now that you are in position, you complete the movement by just standing up.
It's important that you do not lift with your arms. You can try locking your arms if you are feeling that you are lifting with them. The only problem with locking your arms is that if you stay connected to the barbell as the weights hit the ground, you can injure your elbows.
Eventually, you won't have to go through all this process work to get to the bar. You'll have learned what it feels like to get tight and you can just approach the bar, bend at the waist, and get in position. Until then, try going through the steps and see if you can get a sense of tightness in your hamstrings and upper body.
