I think it might of been in neutral. Do they bounce out of high/low sometimes?
Maybe.... SWMBO had this happen to her the other day, after using low box in the snow, and putting it back in high.... so she thought..... she lost all drive..... it wasn't all the way in ( ooh er matron).... hasn't done it since...
I'm not a fan of electronics either, But... it sounds very much like either your battery and/or your alternator has failed - possibly more likely your alternator if your lights were dim. I wouldn't be spending any money on anything but tools at this point in time - until you know what has actually failed...