Basically, all emotions are modifications of one primordial, undifferentiated emotion that has its origin in the loss of awareness of who you are, beyond name and form. Because of its undifferentiated nature, it is hard to find a name that precisely describes this emotion. ‘Fear’ comes close, but apart from a continuous sense of threat, it also includes a deep sense of abandonment and incompleteness. It may be best to use a term that is as undifferentiated as that basic emotion and simply call it ‘pain.’
One of the main tasks of the mind is to fight or remove that emotional pain, which is one of the reasons for its incessant activity, but all it can ever achieve is to cover it up temporarily. In fact, the harder the mind struggles to get rid of the pain, the greater the pain. You will not be free of that pain until you cease to derive your sense of self from identification with the mind, which is to say from ego. The mind is then toppled from its place of power and Being reveals itself as your true nature.
Eckhart Tolle, The Power of Now