The phrase "about my existence" is correct and usable in written English.
You can use it when discussing topics related to one's life, identity, or philosophical reflections on being.
Example: "I often find myself pondering questions about my existence and the meaning of life."
Alternatives: "regarding my being" or "concerning my life".
Bill replies: The thing I really enjoy about my existence, my work, is the variety of it.
She had known nothing about my existence until I made contact the week before but we soon had a strong bond.
Milosz blamed himself for not having been a better parent and described feeling "a terrible guilt about my existence, partly justified, partly pathological".
I wasn't thinking about my existence on a global scale but on a local one.
I returned with clues about my existence, my mind opened -- enlightened, perhaps -- and TB.
What about my existence, or that of any other, declares that who I am must be a fit of sorts for how you perceive the world?
"Every time I decide to share about anything in my life it seems too vague that there's no point really or if I get specific I feel like a twat because I feel like I have so much and how dare I share about my fortunate existence," she writes.
Rather surprisingly (or perhaps not, for this poetic novel) the book presents Harry with a portrait of himself: "a clever study by an unknown hand [giving] the unvarnished truth about my shiftless existence … [showing] clearly how unbearable and untenable my situation was.
Reporters get hate mail (it's a fact of life), so I was already feeling guarded about my online existence.
However, I simply refuse to subscribe to delivering mouthfuls of misery about my own existence.
While virtually everything about my daily existence had been radically different, the service was the same in China as it was in New Jersey.
