When we have that feeling of fear, we feel a loss of control. When we're not in control, we have a heightened (and often exaggerated) sense of fear of the unknown. In a nutshell, fear feeds, and feeds on, itself.
Fear is generated solely from within through our brains, but it manifests as either External, or Internal.
External fears are usually called phobias, and are caused by things outside ourselves, which we're strongly motivated to avoid. These fears are often called phobias, and are usually caused by a past negative experience with an external force. Someone who was bitten by a dog as a child may carry that fear and have it develop into a phobia into adulthood. External fear can be treated by relatively simple techniques, although it certainly requires hard work and serious dedication to recondition these behavioral responses.
Even more difficult to reason with are our internal fears. The majority of us at some point, have had that voice inside our head, telling us we couldn't possibly do that because we're not good enough, rich enough, smart enough, etc. etc. This voice, is the voice of fear. Our internal fears, which are an illusion, paralyze us and keep us from moving forward as human beings - they keep us from achieving our full potential. These fears can include fear of rejection, fear of failure, fear of commitment, fear of success, fear of embarrassment - the list goes on and on.
So where do these fears come from? They come from low self-esteem, which is reinforced by our constant need to compare! When you compare yourself to another, you forget your authentic self. Instead of focusing and building on your own powers of expression, your own talents and your own place in this world, you become afraid that you won't measure up in they eyes of others. And if you don't measure up, you fear becoming embarrassed or humiliated - in other people's eyes. You base your actions on the potential reactions of others, instead of being true to yourself, which is why it seems safer to just do nothing, achieve the bare minimum, take no risks, and never live up to your full potential.
We all know however, the internal struggle, and the inherent unhappiness that comes from ignoring our true selves - you're never at peace, because the authentic side of you is constantly at war with your fearful side.
How do we get rid of our internal fears?
We start by really getting to know ourselves. Make a list of all the things you are afraid of - and be honest with yourself! Are you afraid of truly loving or of truly being loved? Are you afraid of being "trapped" in a relationship? Are you afraid of failing at the one thing you've always wanted to do with your life? The only thing that's stopping you from achieving everything you want and deserve (and yes you deserve to be happy!) in this life, is Fear. Fear is not tangible, it's something we create in our own minds that has no purpose in relation to what we, in today's society, attach it to. Fear is a disease that does not exist in healthy, happy people - just look around you. Do the happiest high-achievers you know let fear dictate their lives? No - they concentrate on being happy and fulfilled within - the rest always falls into place once you've figured this out.
It's up to you to rid yourself of fear - start by acknowledging it.