You might have freaked out because of the sudden change from silence to max volume... but if you do it consciously, to raise the volume bar from null to max, you will find that most DAP's max volume are quite tolerable for reasonable periods of time... I really don't think a single device (a laptop, an iPod, etc.) will let you reach for headphone killing power. I think you need at least some beast of an amp or many amps chained together to do that, or at least to do it to the type of headphones I use: clip-ons, earbuds and Grados.
By doing this test you will not only fight your fear, you might even feel relaxed and kind of euphoric for a moment, due either to the staepedes protective reflex or to some other psychoacoustic effects. Also it will let you hear how loud and well can your phones really perform (it is never good to continue leveling up the volume once you begun hearing distorsion) / how much your ears can really take (takes more than a walk on a busy street or a gunshot to hurt, it take a life in a noisy factory unprotected or a fall into an erupting volcano) / and finally you'll see for yourself if you broke them, which I believe you did not.
Be careful though, go very gradually, stop if it hurts, and pick an atmospheric song with slow voices and soft wind/string instruments, avoid percussions, hip hop, rock, metal.. avoid sudden impact sounds at such levels, if you want to make sure nothing happens to sensible phones. I can say you'll feel better after doing that.
