NoOneFromNoWher

Last November, my 2004 Honda Civic EX appeared to have a dead battery. The car would not start. We called a tow truck who jumped the battery and we drove the car to the local shop. They tested the battery and said the battery was fine and that perhaps a connection(?) had jiggled loose. They claimed to have "tightened everything up" and sent me on my way. A couple of weeks later the car lost all power on the highway (radio, lights, brakes, etc). It was towed to a sister shop and they said the battery and alternator were bad and replaced both. 10 days ago the battery light on the dash would come on and flicker intermittently, but didn't stay on. Drove it to the shop that replaced the alternator as it was under warranty for 12 months. They tested the battery and the alternator (and the starter?) and all of the results they say were good. They said they "tightened everything up" in case it was just a loose connection, gave me a copy of the results and sent me on my way again. The light did stop flickering after that so I hope everything was resolved (especially as it seems like the alternator shouldn't fail again so soon?!). Last night the same issue of last November happened again on the highway -- lost all power to the car. Left it overnight and when the tow truck driver came this morning to tow it, it started right up. I had him tow it anyway as I wasn't comfortable driving it again. But, if it lost all power last night and wouldn't start then, why did it start this morning? If the battery/alternator test last week were fine, why did it lose all power last night? And why does this seem to be the EXACT same issue of a year ago? What is causing this? What should we do? We can't afford a new right now, but it's just not safe to driving along on the highway and have the power to the car just cut out without any warning.