First of all,
your decision to quit something wouldn't be questioned by anyone who's spent any time here and read your posts.
You're not someone who'd be characterized as reactive and it's obvious you're a thinker and would weigh the pros and cons and mull it around before quitting something you've committed to.
In answer to your question, that's the difference between a quitter and someone who comes to a realization that something isn't right for them. One is a spoiled brat (okay, yeah I know one) who quits when the going gets tough or when they become bored or have to work too hard. The other spends time and often agonizes, realizing that perhaps this wasn't what they really wanted and has a true and realistic understanding of the situation.
I've switched careers, husbands and lives several times. Each time it took me years to get up the chutzpah to do it. When you know, don't question yourself and stay miserable. Please, don't remain a people pleaser. You're a brilliant girl. Take care of you FIRST. *hug*