Lua, to add to what BTB said about your deadlifts, most people who are learning to deadlift start with their hips to low. This is usually because they've been told over and over that you have to sit way down to protect your lower back. But it's simply not possible to deadlift with your hips that low. Your knees will get in the way, and it's generally not the best position to take advantage of the strength of the lower back, glutes, and hamstrings.
Most fitness magazines tell you to start like this;
If you're lifting with a trap bar then you can totally pull this off, but it's not going to work with a normal barbell, and it isn't the way to pull the most weight anyways.
Here's the best deadlifter in the world, breaking all the rules you'll read in men's fitness;
His butt is not sticking in the air, but it's also not low. It's right in between. Also, his head isn't up. The less bends in the spine the better, which is why he's looking towards the ground in front of him and NOT up like you see in most pictures touting "good form".
He also has an absolutely perfect hip hinge, which means his hips are tilted forwards and his pelvis is facing the ground in front of him. THIS is what protects the lower back and allows you to access the strength of the entire posterior chain. People talk about an arched back, but having a good arch is a byproduct of a good hip hinge. The hips are the key.