I'd also suggest checking the dice logs if you think something's gone wrong - I often do that myself. I don't remember for sure if I've seen it for Counterspell, but if there was a roll required for Counterspell it will surely be in there - so you can work out whether you just failed a roll (and if so it should say what level of spell you were rolling against), or if there was indeed a bug or some other reason Counterspell just failed.
