yupp sounds like the alt, when i had a mustang my alternator took a crap on me while driving, first everything shut off like all the lights an radio, then the car was bogging at idle, unless i would keep it reved at the light an launch from a stop the car would bog a die out.
so yeah ur story def sound like u need a brand new alternator an check the cables that run to the alternator cause when this happended to me one of my cable some how got like burnt out, like fried an coroded.
hope that helps,
if not check the kanooter valve, lmao