American Wheat corroding most weak metals

So, early Sept. I made Northern Brewer's American Wheat all grain kit. Everything seemed to go well. Yet after having been kegged for close to a month now it taste like I'm drinking hydrochloric acid. I've given it to a couple of people to try, and they all say the same thing, "tastes acidic".
Just a little background info, I used only distilled water, and used 5.2 to adjust the mash pH (maybe that's why it's acidic?).

Any thoughts?

 

Too little info - lay it all out for us and you might get a good answer.

-OCD

 

Distilled water could be part of your problem. The entire brewing process benefits from minerals in the water.

Here's a brief article:

http://www.brewersfriend.com/2009/03/14/all-grain-water-chemistry-brewing-information/

Additionally, www.howtobrew.com has a significant section on water profiles.