Odds of Hanging On
It's called the Perpetual Profession of Vows for a reason. Unless you slip up on the vows and do something you explicitly said you wouldn't do—like get married or own an investment account—you're in it for life.
Does that mean you can't ever get out? If you've decided that the frock doesn't fit, there's a way back into the world. You can follow very specific steps, hand in the right forms, and make the right declarations to the right people, and you'll be released from your duties as a nun or a monk.
You'll be sent to rejoin the world...with no job experience, no health insurance, and no bank account. If only there was a place you could go that would provide some charity to you in your time of need.