HELP! Reverse Light Screw-up

Hi, I was trying to install a reverse camera on my 2008 altima and I got to the point where I needed to tap into the reverse wires for power. I put my car into reverse, and went ahead to look for the positive wire for the reverse light using a light test tool. However, while touching the prongs, I noticed the reverse lights completely shut off (both right and left, mind you I was only working on the left side). I then walk into my car and I see that all my gauges turned off and are completely stationary. My speedometer do not light up or respond, my odometer does not work, my fuel gauge doesn’t work, nothing!

What can I do? I am so desperate to fix this!

That sounds like you blew a fuse. Look in your owner’s manual for the fuse locations (often near the driver’s left knee) and find the one for those circuits, often called the “gauge fuse”.