H&R lowering link issues

[shooter]

i have had this h&r lowering kit on my 02 4.4 w/ rear air for 2 months now. the back end seems to have lifted back up. I tried to drop it more but it the bags don't seem to want to let the car down. In fact, it actually went higher when I tightened them up earlier. After I drove it around the parking lot the back finally dropped right where I wanted it. i drove down town and it was perfect. when i got back to my friends shop it was back up in the air. I'm confused. 2 months ago i could tighten the links to max and it would almost be tucking wheel, but now it doesn't seem to matter what length they are. The truck seems to sit where it wants. Also the right side is always higher than the left. The leveling code came on a few months ago when I first installed it, but it went off. I hear the compressor working so I don't think thats the problem. Can someone please tell me why my link adjustments are having an affect anymore? Why can't I lower the rear end anymore?