Problem with my TSB springs

My 2010 came with the junky 3-pack springs. I had the TSB done roughly a year ago, and all was good until fairly recently. For some reason now my truck is sagging really badly in the rear. The front end is considerably higher than the rear now, and the left side is probably half an inch lower than the right side. My poor truck looks like hell now, with a "bro lean" and a lean to the left. It looks like a massive man is sitting in the drivers' seat or something.

I haven't changed anything as far as weight goes, either. I have had a toolbox full of tools as well as oxy/acetylene tanks in the rear, but they have been there for ages. Nothing has been increased, but the springs are sagging more and more as time goes on.

That being said, what can I do? Will I be able to get the dealership to replace the springs for me again, bend them back to pre-sag specs, or would simply buying a set of Bilsteins (I don't have TRD, so the truck has the generic Toyota shocks) lift the truck back up? I was hoping maybe they could do some creative paperwork and get me a new set of TSB springs.. Assuming that they just scrap all the old parts and wouldn't have to send them back to Toyota. It doesn't seem like it'd be economically feasible for them to mail a ton of leaf springs back to Toyota. I also have the feeling that the issue lies solely with the springs and buying new shocks won't do anything.

Any help/advice is greatly appreciated.

 

Did it happen all of a sudden? You sure you dont have a busted leaf?

 

A busted leaf would cause much more of an issue than just a sag I think, especially riding around on the farm and whatnot. It wasn't THAT sudden. It's just been in the past couple weeks I've paid more attention to it, and noticed that my front end was higher than the rear, which has NEVER been the case with this truck.

EDIT: I got a set of 5100s, front and back, from here: . I got the C476 (the first ones listed) for my rears. They seem to be longer than the stock ones, is it safe to assume that a 1.5" AAL kit would not make them hyper-extend if I end up having to go that route? I was unaware that an AAL was only $80, which I don't consider bad-- I am likely going to try the 5100s for now, and if I'm not happy with the way the truck sits I'm just going to go for an AAL. If you guys think the 5100s I chose will work with as much as the 2" AAL, I will definitely do that instead of just the 1.5", but I don't see that being possible.