WOW! This is beautiful and heartbreaking at the same time. With this piece you have really put your heart on your sleeve, showed all your raw emotion.
I really liked the link between the ocean and yourself as it was written seamlessly and, it appears, without much effort - an amazing effect. Also it gives off such vivid imagery and works as a perfect metaphor for your current situation and emotional state. I almost sense a nothingness which I feel reflects the tone and/or content of the poem perfectly.
Another part I particularly enjoyed reading was the fifth stanza:
'Because your memories never die
and never faded
Ask my pen
It will write my shadows of death'
You almost personify the pen, but not quite. You are more likely saying that your hand won't stop writing like your heart won't stop beating faster at the sight and thought of this person. Also I feel this directly reflects writers, poets in particular and that many can relate.
I must say I like the use of the title statement throughout - it's not overbearing and pushed in the reader's face, it's subtly and flawlessly incorporated into the piece almost like a shadow itself. It's written with such elegance and really reflects the mood and content of the piece perfectly.
A few suggestions, though please ignore if you wish, in the 8th stanza:
I think it should be 'fell in love WITH you'
and I feel as though it would sound better if you changed 'time' (in the last line of the 8th stanza) to moment. I feel this will also reflect that you are unable to avoid thinking and/or loving this person even for the shortest time. It's up to you though, of course.
Overall, a genuinely amazing poem, my friend. Your writing keeps improving with every piece and its an absolute joy to read your work. This one I must add to my favourites. Beautiful work.