How can I gain stability mentally and emotionally over things that affect me deeply?

Mindfulness

Mental insecurities, fear of rejection, etc., come from a place of not being enough. In short, you believe something about yourself that isn't true, and until you separate from this belief and thoughts developed from this belief, this issue gets better. It's a cliche these days, but we do have to learn to experience, accept, and love ourselves genuinely. How we get from where we are now to this healthy place of loving ourselves is the journey of self-exploration. 

A couple of questions to ask yourself are, Are you worth this journey? Are you wanting to change or avoid the consequences of what you are doing? What are the implications of your current way of living? Are you getting the attention you like when you act from a place of rejection and stress? As harsh as some of these questions seem, they insinuate intention, which can be hard to accept when we feel like we are a victim of circumstance or mentally unstable due to some organic disorder. Nobody wants to hear that their decisions keep beliefs and behaviors alive that they want to get rid of. Behaviors are formed from rewards; somewhere in life, these behaviors and self-perspectives do get us something. When you are honest with yourself and ask yourself the right questions, what do you come up with? 

Mindfulness is being able to sit with ourselves, all parts, and learn to appreciate them and where they came from. Even our worst parts, those inadequacies, were formed for some reason. There has to be an appreciation for these parts because they are all you and all necessary. 

The road out of hell is like using a metal ladder without gloves. This is a phrase used in a mode of therapy called DBT. The author of this therapy specializes in personality disorders and how those deep personality traits cannot be fixed with medication but with mindfulness and coping skills. This is the same thing you are dealing with; your deep insecurities come from a faulty belief about yourself that you believe to be true. Mindfulness is noticing our thinking. Not what we think about, but we see how we feel. 

Once you can sit with troubling emotions, no matter how triggered, you have found your bulletproof vest in a life full of piercing comments. Remember this, your beliefs about yourself and the world around you, formed in childhood, affect your thoughts, which then trigger your emotions which cause you to react. It is this reaction from an emotional or inadequate place that can be troubling and destructive. Imagine you are feeling a certain way, notice it, separate from the thought, and don't react to it. The impact this will have on your life and relationships will be exponentially profound and positive.

Lastly, the relationships that you can form when able to cope and put others' needs before yours because you are safe and able to love yourself first. Real, authentic, long-lasting friendships can make you feel loved and supported, reinforcing this new perspective of yourself. Remember, you can be all the parts you experience, even the "poor" or "weak" ones. It is actually from these parts that we grow strong. Those insecurities can be appreciated because they force us to work hard and notice things others overlook.