Same thing happened to me not 2 days ago. Sounds like it's the battery because there are other symptoms as well such as the a/c blower intermittently cutting out and long hard cranks in the morning (also had a yellow battery light not too long ago).
I'm getting a new battery installed this week and hopefully it all goes away.
Did you get your new battery coded properly? You can use aftermarket but from what I hear you have to get it coded to the cars computer for it to work properly.
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