The Self

As the self does not become itself; it is potential rather than actual, doesn't that mean that the 'true' self is only as a figment of our imagination? Part of the true self ('I wasn't acting myself yesterday' 'It wasn't me that did it. It was the alcohol/hormones/peer pressure etc') lies in the future and in the past as well as the present. At any given moment in time we deviate from this 'true' self. It therefore cannot exist as part of the space-time continuum. Is this not what we mean by the immortality of the soul? Isn't it!