That feeling of confidence, self assured ness and freeness that substances bring is nothing but an ephemeral mirage, Dim.
The feelings are an illusion; they do not last, nor are they real. The dependency on that short lived, instant 'boost' is the lie that keeps us from acknowledging the true issues that underlie the cravings of this short term appeasement. Don't give in to it. Work through it and take this opportunity to analyse what you are really feeling, rather that sedating and anaesthetising it with alcohol and other substances.
Any relief that they bring is not adaptive in the long term, and rather serves as a road block that will hinder your self awareness and development. You need to address the root cause of these feelings so that you can work through them to get to a place where you can feel whole without the enhancement of substances.
Who you are should be the person you are when you are clean, sober and aware - not an inebriated or altered state of your true self.
Pour anything you have out and recentre and try to face some of the triggers that lead to this relapse. Wishing you well.