The phrase "light of my life" is typically used as a term of endearment to describe someone who brings brightness, joy and meaning to one's life. However, as with most words and phrases, there are antonyms, or words with opposite meanings. For instance, words like "burden," "heartache," and "anguish" could be used as antonyms of "light of my life." These antonyms suggest that the person in question is difficult to deal with, causes sadness, or is a source of pain. Other antonyms could include "darkness," "gloom," and "despair," all of which imply a lack of happiness, positivity and hope.