Shakespeare's Sonnets: What potions have I drunk of siren tears

What potions have I drunk of siren tearsDistill'd from limbecks foul as hell within,Applying fears to hopes, and hopes to fears,Still losing when I saw my self to win?What wretched errors hath my heart committedWhil'st it hath thought it self so blessèd never?How have mine eyes out of their spheres been fittedIn the distraction of this madding fever?O benefit of ill, now I find trueThat better is by evil still made better,And ruin'd love when it is built anewGrows fairer than at first, more strong, far greater. So I return rebuk't to my content And gain by ills thrice more than I have spent.