Messed up brakes
 

Hello, Thank you for taking the time to read this. I'm new to fixing my own car and I think I messed up.
I have a chevy Trailblazer 2007 LS 4wd with 200k miles I drive a lot maybe 5 or 6 hours a day and I love my truck and would like to keep it longer.
I installed new rotors and pads from autozone 6 months ago, everything was working great until I needed new pads after 5 months. This time I got new pads from Advance auto parts and I kept the same rotors bcz they were still good. Only 5 days later my brakes started pulsing, I can feel the pedal pulsing and steering vibration so I went and bought new rotors from Advance and kept the same almost new pads. It worked great but 1 week later the pulsing is back and it's getting worst.I'm now confused there's so many possibilities It could be the brake pads are causing the rotors to wrap for some reason, it could also be that I tightened lug nut so much, or my brake lines and caliper are bad.
I dunno where to start please any suggestion is very much appreciated.

I would definitely check the rotors and flexible fluid lines to the front wheels.