Gah, after HOURS of struggling...
I had to tweak your lyrics abit and make them short as possible, while keeping the meaning same.
The translation were pretty direct, I dont know about poetry skills.
ahh, as you can see my grammar sux
Hope somebody could correct me on this

I do have a Japanese teacher but I havnt been to lesson for years..


I laugh and the sweet sadness ends,Is that how happiness works?
私の笑いが、悲しみは終わる。 幸せの概念ですか？
Watashi no warai ga, kanashimi wa owaru. Shiawase no gainendesu ka?

Once more, I've fallen for you.
もう、私はあなたを落ちた。
Mō, watashi wa anata o ochita.

Once more, another heartbreak comes.
もう、別の失恋が来る。
Mō,betsu no shitsuren ga kuru.

Through lonely nights,I only find comfort in myself.
孤独な夜に 、私は自分を慰める探し。
Kodokuna yoru ni, watashi wa jibun o nagusameru sagashi

I can make my own happiness,
But it isn't as good as yours.

Silence begins and the damage is done.
沈黙が起動し、損傷した
Chinmoku ga kidō shi, sonshō shita

Like a quiet audience,
静か聴衆のように
Shizuka chōshū no yō ni

only our eyes speak our thoughts.

And the heartbreak begins
失恋が始まる
Shitsuren ga hajimaru

Broken telephone,
Is what we've been playing all along.
I can make my own happiness,
but not as good as yours.