Most of this poem reads like a night out in Las Vegas that goes badly. The speaker flies in full of hope, dazzled by the city's lights, then moves from slot machine to cards to roulette. Each time the luck fails, and each time the speaker bets bigger to win it back. The debt grows, and the speaker leaves with nothing and a sinking head.
The short, clipped lines work like quick bets, one after another, and the repeated "-ing" verbs make the losing streak feel endless. The mood shifts from excitement to desperation to a quiet, tired disappointment.
Then the ending turns everything around. The gambling list grows from money to possessions, life and happiness, and the final lines reveal that the real "big gamble" is love: "Giving you my heart." The speaker seems to treat love as the biggest risk of all, one worth taking even after so many losses. The closing mood is hopeful, but also nervous.