There is a change--and I am poor;
Your love hath been, nor long ago,
A fountain at my fond heart's door,
Whose only business was to flow;
And flow it did; not taking heed
Of its own bounty, or my need.
What happy moments did I count!
Blest was I then all bliss above!
Now, for that consecrated fount
Of murmuring, sparkling, living love,
What have I? Shall I dare to tell?
This is another balanced, rhythmic line. Note the  alliterative  and  consonantly  rhymed ‘blest’ and ‘bliss’. He speaker was in a state of extreme happiness.
A Complaint