One day, you will wake up and realize you are still breathing, though moments before it seemed impossible.
One day, you will hear yourself laugh, then catch yourself, stopping short, gasping in sorrow. How could you laugh, after this? But laugh you will, and you will say a silent thank you to whatever gods there be, that such a thing is still possible.
One day, you will make a decision about the future of your life and know that it includes the sorrow you feel now, not that you have moved through, moved on, or gotten over it--simply that life includes all that you now know. That happiness and missing someone aren't mutually exclusive. The two can be combined, bittersweet, the knowledge of one tamping down the vitality of the other.
One day, you will realize that you have done the impossible: you have survived, simply because you are still here.