I don`t think that instinct has something common with stress. When you`re stressed you make mistakes trying to win more or to return your loses. It is not about instinct but mostly about greed and mistakes.
But you`re right that it is near with gambling addiction and we have to pay attention to such signals.
You are correct. Instinct has nothing to do with stress; stress keeps one in a confused state, which is why gambling in that condition is not advisable because your judgement can be easily affected.
One should be resting in that state and not gambling; instinct basically is just like a thought that comes to our head and suggests what to do, which is left for us to either follow it or leave it and do what we think is better off, even as it can be correct most times.