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,
The punctuation is worth noting. The exclamation mark suggests energy and a burst of good memories. 
 The fact that the writer can count the moments of their love suggests the speaker was previously blinded; unable to see the bigger picture.
A Complaint