It is a recent development in history -- the concept of the person as composed merely of flesh, blood, experiences, emotions, and thoughts. Previously, people conceived of themselves as spiritual beings in a larger cosmology. While this view is still quite common, there are a growing number of individuals who are raised to believe that they are what they experience. That our being and sense of identity is primarily what we think, feel, experience, and know.
The fallacy in this approach is that when a history of negative experiences occur in one's life, that person can easily misconstrue that therefore one's identity and complete being are negative, fearful, uncertain, and inadequate. The rationale goes - if there are no consistent experiences of the positive, and if experiences are the whole of one's being, then the negative is all there is.
Consider for a moment that we are not what we experience. That there is some greater unknown in our existence that cannot be described. That what you know and believe could be a story that you tell yourself to explain how things have come this far.
What other explanations could there be to tell you who you are?