My breakdown.

Oh, my dearest love
The answer is someone or something that is very dear. The person or thing is loved by the speaker.

The secret things you've been hiding
The answer has secrets that they've been hiding.

Lost in memories, but still so close
The answer is lost in memories, but is still spiritually close by.

If I look, will I find you?
If the speaker looks, they would find their love — which is the answer.

If I find you, will I lose you?
Yet, if the speaker finds their love, would they loose it?

Something brings to mind the Lifestream in general.