What happen??

On my way to pick something up from work i noticed my cd player suddenly stopped working , then my signals wouldnt work then my watch and so-on , then when i turned of the car it wouldnt start i got a boost and then drove but once again nothing electronical worked , then later in the evening it wouldnt start again , got a boost but this time it didnt last the engine would shut off after a few minutes. Does anyone know what it could be , my first guess would be the alternator???Any help is greatly appreciated as usual. tia