Abhinivesa is the sanskrit word for fear. It is one of the five kleshas, or mental afflictions, which give us a sense of discordance. They are the thoughts we think we're stuck with before we discover there are techniques to help us release their control over us. That is one of the first things I remember really sticking with me when I began my initial teacher training. We don't have to be stuck with our thoughts. We don't have to be at the mercy of our emotional waves. With practice we have power over what we may perceive as having power over us. It's such a liberating thought.
I have to remind myself that I am determined to behave in a way that reflects my practice and is not dependent upon anothers' actions. This is particularly difficult to bear in mind when dealing with the people who I am emotionally attached to.
When I worked in the hospital there was a remarkable amount of "I won't do that cause they won't", and subsequent complaining about "them". But perpetuating the behavior of a jerk only makes you an jerk.
When I allow others to dictate how I behave, I am motivated by fear. I fear I won't be liked. Everyone wants to be a part of a group. Even those who like to be alone want to be accepted and appreciated. We have to bring that acceptance to ourselves. Yogic teachings say that when you realize your true essence you will never feel lonely again. Take a step toward that awareness by clearing out space that has been filled with worry, fear and reactivity.
You have to cultivate an understanding that all your worries are based in fear. The ultimate fear is that of death, but the general fear of the unknown is infused into all of our decisions. This boils down to avoidance and attachment, which the sutras say are the obstacles to overcome if samadhi (becoming one with the essence of existence) is going to be achieved.
Maybe samadhi is too lofty a goal for you. Just moving through your life with less fear can help to open you to the moment, allowing you to act purposefully instead of reacting.
There are many techniques yogis have to help face and integrate fear.
Bramhuri is a kriya (cleansing practice) that helps reduce external distractions and clear away mental disturbances. Plug your ears and hum.
Long exhale: extending the length of your exhale relative to that of your inhale will help to sooth your nervous system and calm your mind.
Chandra bedhana: Inhaling through your left nostril and exhaling through the right will help facilitate calm and promote sleep.
Asana awareness: Staying observant during asana practice can help you to realize where you hold your fear in the body. How do you approach poses that you are afraid of as opposed to those you look forward to.
Contemplation: Who do you allow into your space when you're alone?
How big is the gulf between what you think/do when you're alone vs with others?
How much guilt to you subject yourself to?
Do you fill silence with worry?
Answer these questions without judgement. Become aware of what is without fearing repercussions.