Life goes on they say. But sometimes it does stop, or you may also say, gets stuck. You get stuck, not because that part is sad but it's sad because it's important and you can't have it again. But when you know you can't have it back, then why stop and wait, instead- walk, run, fly with it, hold it and never let those beautiful memories fade away. Cherish them, keep them fresh, but certainly don't let them make you weak, let them be the reason of your achievements, the reason of your ignited mind.
Our serendipity, our luck in finding the most beautiful, most valuable things by chance, should be a reason of our smile, not the tears. We never lose them entirely, as it's our choice if we want the memories to stay or not.
If it ever grows on you in a negative way, either stop yourself, get up, take a deep breath and tell yourself, it wasn't my life, but a pulchritudinous part of my life. Or, let loose of your feelings, let them overtake your mind. Cry, scream, listen to the song that reminds you of it, and in a while your heart would be at peace. You'll feel the explosion melting away.
Let your serendipity be the most wonderful thing that ever happened to you. Enjoy it, as you were fortunate enough to have found it.