Is it possible you might have accidentally connected the 3.3v power input on the module to 5v from the breadboard supply? If so that'd do the sort of thing you're experiencing - working for a bit and then breaking...
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Is it possible you might have accidentally connected the 3.3v power input on the module to 5v from the breadboard supply? If so that'd do the sort of thing you're experiencing - working for a bit and then breaking...