What potions have I drunk of Siren tears (Sonnet 119)

What potions have I drunk of Siren tears,
Distill’d from limbecks foul as hell within,
Applying fears to hopes and hopes to fears,
Still losing when I saw myself to win!
What wretched errors hath my heart committed,
Whilst it hath thought itself so blessed never!
How have mine eyes out of their spheres been fitted
In the distraction of his madding fever!
O benefit of ill! now I find true
That better is by evil still made better;
And ruin’d love, when it is build anew,
Grows fairer than at first, more strong, far greater.
    So I return rebuked to my content
    And gain by ills thrice more than I have spent.