What was your carbonation pressure and temp?
I've overcarbed beers and it's hard to get them to settle down. To check carb level, I purge all the pressure from the keg and set the regulator so that it's just enough pressure to push out the beer - usually a pound or two, depending on hose length. After the initial bit of foam, the beer pouring slowly into your glass should have a nice carb level and almost no foam at all. That method will work on any hose length or even a tap directly on the keg. It'll allow you to see whether you're dealing with an over-carb situation or just serving pressure/hose, etc.