Power Steering Fluid Issue

In the last 3 days i've put almost 3 quarts of power steering fluid with stop leak in my 2003 Chevy Trailblazer. As I got home this evening, turning the corner I had to use both hands to turn the wheel, and again when I pulled in to the driveway. After unloading the days shopping, I popped the hood, opened the fill valve for the power steering fluid(which made a pop sound like a soda can) and could smell burning, like the fluid was being heated to the point of burning or evaporating. What is the possible cause and what can I do it fix it?