You are you.
You happen to be INFJ.
INFJ is a set of cognitive functions, that is most likely relevant to some physical structure, or at least a certain way the brain is stimulated in very early stages. (warning, that's only my personal hypothesis)
INFJ does not define you. You define INFJ.
I know INFJs who go through similar cycles. I've read the biographies of some INFJs who even went to mental institutions at an age between 20 and 30, and later, especially getting older, they've become extremely influential and respected social figures. This still doesn't mean anything, just an example.
You're probably right to protest against grouping such as MBTI, especially the way we try to use it. Creating some sets of supposed roles for each type is degrading our individuality.
For example, I always thought of myself as extremely rational, and rarely found someone to challenge me in such a way, that I'd question my own reasoning. And then I discovered MBTI and the claim that I don't belong to the "Rationals", because I'm more concerned about the well being of humanity. If you ask me, the other position is much more irrational. And so ENFPs are these mindless irresponsible butterflies, and I'm just supposed to accept that nonsense? My past record (before I knew about MBTI), apparently, disproves that assumption. With hard facts, results. So should I trust the real data, or the theory? The data, of course.
So just follow your own needs, and don't be bothered by the stereotypes.