Sonnet LXXVIII: "So many changing phases have I known"

So many changing phases have I known
Of my hot heart and of my colder brain,
So long and strange has been the varied train
Of feelings that from each to each has flown;
So oft has reason held the rein alone
So oft my heart endured the fret and strain
Of boundless gladness and as boundless pain,
That I begin to doubt myself my own.
The sage of yesterday, today is changed
Into the likeness of as wild a fawn
As ever through the Thracian vinyards ranged;
And I betwixt the two am tugged and drawn,
Hither and thither, from both sides estranged,
Seeking which way my former self is gone.