credit spreads and iron condors, are we just pickup up gains to lose it all in 1 go later?

I am doing .06 delta credit spreads and making like 1 to 2% a day , but I computed that if SPX goes up by 2% in 1 day , either up or down, I will lose half the capital. And 2% a day happens like 18 times on average in a trading year.

Has anyone did some probability of this ? Seems like a zero sum game or even a negative sum game.