It absolutely exists; I lost almost all my balance because of that. twice now.
I got too many 7s in roulettts and lost too a few days ago.(lucky this one was a bonus code)
Edit: You got that 'Gambler's fallacy says that' part wrong. It is just the opposite.
It's called a fallacy for a reason. According to it, people believe that chances of something happening again become are reducing as it repeats while it's just the win/loss chances that should be taken into account individually for each bet.
But anyway, people shouldn't rely on my explaination, that's why I posted a wikipedia link.