You are very lucky to make such a big win. This something you played unknowingly and you made a win. It is very rare for people to make victory like this, mistakes like this usually make people to loss more .it is also nice that withdrawing the money was not a problem for you .congratulations, you deserve a win.
I agree with you that when anyone make mistake like this usually becomes a loss. Even several times mistakes made me a loser. But you are the luckiest person that is why you become the winner and you have not faced any problem in withdrawing the fund or anything else. You are really a very fortunate person.