You've done the right thing - all important points have been covered by everyone else, but as they say, it wouldn't have looked good for you to ask for time off in your first week, whatever the reason. And I agree with others, if your boss doesn't play poker, then asking for time off to go gambling was definitely a massive no-no.
Nice one on managing to cash the seat in, now you can either save the dough and buy in for the next one, use it on DTD to play loads of sats for the next one and the 300s etc, or just buy loads of pizza. Result all round!
Knowing the OP, very much this ^^^^^^^^^