What does this poem mean? I don't understand any of it, please help!?

I can't even look for imagery, sound devices or even know the theme because I just don't understand it!! :( Thank you

Soeur Louise de la Misericorde (1674)

I have desired, and I have been desired;

But now the days are over of desire,

Now dust and dying embers mock my fire;

Where is the hire for which my life was hired?

Oh vanity of vanities, desire!

Longing and love, pangs of a perished pleasure,

Longing and love, a disenkindled fire,

And memory a bottomless gulf of mire,

And love a fount of tears outrunning measure;

Oh vanity of vanities, desire!

Now from my heart, love’s deathbed, trickles, trickles,

Drop by drop slowly, drop by drop of fire,

The dross of life, of love, of spent desire;

Alas, my rose of life gone all to prickles,—

Oh vanity of vanities, desire!

Oh vanity of vanities, desire;

Stunting my hope which might have strained up higher,

Turning my garden-plot to barren mire;

Oh death-struck love, oh disenkindled fire,

Oh vanity of vanities, desire!

(mire: mud)