Hare Krishna. All glories to Srila Prabhupada!
The four regulative principles of no meat eating, no intoxication, no illicit sex, no gambling, seem to suggest that gambling is not a good idea. These four illegal activities increase lust and greed and the desire for material, bodily conscious satisfaction rather than spiritual growth. So by disciplining ourselves, we purify our bodies and hearts to be more susceptible to the truth when we hear and chant, etc. We must be pure in order to know the truth. So any breaking of the regulatory principles is like a veil over our eyes to see the truth.
Use your winnings to serve the Lord. Even when you're golfing, think of the Lord. Everything we do can be dovetailed to serve the Lord. I'm in school right now and I try to think that I'm writing some test for Krnsa, I am writing a thesis for His transcendental pleasure. Even if an activity is not overtly about Krsna, think of it as an offering to Him. Thus we will be steady minded and think of Him always. Happiness and distress come and go but Krsna is always there in the heart.
Another thing, about chanting. You should try to concentrate of Krsna while chanting. Doing some other activity means only part of your mind is attentive to the holy names. Srila Prabhupada suggested that if your mind wanders while chanting, bring it back to just focus on the sounds. If the names are purely chanted, Krsna dances on the tongue of the devotee! Hari Bol!
I don't know if any of this made sense but just some thoughts.
Hari Bol!
Aspiring to serve the Vaisnavas,
gopi