Identifying the Causes of J. Alfred Prufrock's Depression

Upon first reading “The Love Song of J. Alfred Prufrock” I just saw a very ugly and negative outlook on life, but once reading it a couple of times I became interested and wanted to determine the cause of Prufrock’s depression.
One of the first repetitious phrases presented in the poem is “In the room the women come and go/Talking of Michelangelo.” I perceived this repeated line to be very meaningful because throughout the poem he conveys loneliness and the desire to be with women, but here he is noticing that the women only talk of Michelangelo. Prufrock is comparing himself to a great and well known artist and sees himself as a lowly middle-aged man, which only adds to his insecurity.
Prufrock then goes onto describe the city, but he describes it in a negative light only emphasizing the yellow fog and soot covering everything. This negative view of his surroundings shows his pessimistic outlook and his inner depression.
Another thing that comes up a lot throughout the poem is the word “indecision.” This word explains Prufrock’s thoughts perfectly. He can never make a decision on what he should do, but instead contemplates over it for a long time and then convinces himself in the end he cannot do it. He justifies this backing down by stating that there is time for it, but at the same time Prufrock really fears time. He constantly brings up the fact that he has bald spots in his hair “[w]ith a bald spot in the middle of his hair…Though I have seen my head (grown slightly bald),” and he also states “I grow old…I grow old.” These lines show that while he puts off socializing with women and tells himself that he has time, he also recognizes that his time is essentially running out.
Another main element that adds to Prufrock’s indecisiveness and depression are his constant worries about being judged by others, and his inablity to value himself. An example of this can be seen when he states “(They will say: ‘But how his arms and legs are thin!’)” and later when he talks of the mermaids singing “I do not think that they will sing to me.” These statements make me really sad and compassionate for Prufrock’s lowly view of himself.
An additional element I found that adds to Prufrock’s depression can be seen in the repetition of the line “‘that is not what I meant at all. That is not it, at all.’” It seems to me that Prufrock constantly wants change to happen and really views life in general as just routine when he states “I have measured out my life with coffee spoons.” Basically, Prufrock just wishes to express all of his inner thoughts and change the society he lives in, but instead just sits there going through the motions of a life he finds valueless.
Although the poem is filled with depression there are two short scenes that are presented pleasantly, and those are Prufrock’s dreams of the sea. However, these dreams are abruptly ended when his thoughts return back to the present. The conclusion of the poem once again incorporates Prufrock’s dreaming of the sea “by sea-girls wreathed with seaweed red and brown/ Till human voices wake us, and we drown.” This ending is very fitting to the poem because Prufrock is wishing of an alternate life, but is awakened to only to realize the terrible life he leads and that realization for Prufrock is a form of death.