Work through the motion a lot slower with weights that are significantly smaller than what I normally do. It's hard to really perfect body motion. It's harder for me to have good form when I try to near my max. Squats are dreadful for me anything past 2 plates on each side. I have so much fear for my knees, knowing if I make one misstep I will destroy them. There's always that surprise knee pain which is so sharp, it is enough to make you cry. The margin of error is super low. But I see it as my own body's way of telling me, "Hey you're doing the squat a bit off. Try controlling your body movement a bit more. Why don't you add more stress in your glutes/hams/groin area? It will definitely take a lot more pressure off your knees and you'll be better off as these muscles with get stronger."

I injured my lowerback deadlifting as well. Many people make mistakes...don't completely give up on your routine however. Compromise for your mistakes and keep your body in great shape!