car stereo. wire harness issues Wiring issues please help

[Hoover and sons customs]

Ok so i decided to install an after market stereo into my 07 2500hd. I had a pioneer 2-dim and an amp so i go to my cousins stereo shop and pick up 4 door speakers 2 12 in subs and some wire and a plug. Now ive hooked up stereos before  no big deal, or i thought. Wire up, plug in, it sounds awesome!! Till im driving down the street. Lights on dash come on, gauges drop to zero like i just shut off the truck. I freak out pull over and shut everything off. Smell around for burning or smoldering wires, nothing. So i start the truck back up turn off the stereo, evetythings fine. Turn it back on, goes goofy, so... What i meed to know is, where did i go wrong, and what do i need to do to fix it?

Please help, this is my daily driver and right now o t wont even start