Analysis of Holy Sonnet XIX: Oh, to Vex Me

Oh, to vex me, contraryes meet in one:
Inconstancy unnaturally hath begott
A constant habit; that when I would not
I change in vowes, and in devotione.
As humorous is my contritione
As my prophane Love, and as soone forgott:
As ridlingly distemper'd, cold and hott,
As praying, as mute; as infinite, as none.
I durst not view heaven yesterday; and to day
In prayers, and flattering speaches I court God:
To morrow I quake with true feare of his rod.
So my devout fitts come and go away
Like a fantistique Ague: save that here
Those are my best dayes, when I shake with feare.