Wiring issue, need help

Electrical has always been my Achilles heel....

Everything working good until the other day. As I was driving my stereo turned off and then turned back on. It continued to do this and would not stay on for more than 4-5 seconds. I traced all the wires, found a loose ground connection so repaired and everything seemed to be fine.

Went to pull the car out of the garage and as soon as I tapped the brakes the stereo died again. Traced the wires under the dash but found no shorts or loose wires but every time I tap the brakes the stereo would die.

The next day driving to work, noticed that my headlights seemed dimmer than usual. I stopped for fuel on my way home and when I went to start it...nothing. Dash lights came on as well as heater fan when I turned the key but nothing on the ignition (no clicks, ticks or anything). After third try the car fired right up

Headlights are barely on now, and ignition is completely dead but all instruments are working fine (except stereo which wont even turn on)

Kind of stumped here, any input would be greatly appreciated!