As requested :] I actually did this translation a while back and found it on my Ameblo xD; so I did the roomaji and am reposting it here :D
漢字
深夜の彼のメ-ル眺めて ため息の君
ずるいお別れ たった一言「さよなら」なんて
君の手帳 まだ彼との予定で埋まってる
本当は 僕の名前に書き換えてほしい
ほら 泣き腫らした瞼なんて
気にならないくらい 君は綺麗だから
長い髪をかき分ければ 見えるはずだよ
いつも I keep my eyes on you
壁に刻んだ二人の名前 消せなくても
雨が流すよ やがて新しい夢始まる
忘れられた誕生日も 僕と一緒だったら
下手な歌で 朝が来るまで祝うのさ
ほら 暗い夜に負けそうでも
導く僕が となりで笑うから
過去を抱いて凍る愛も 溶かしてゆける
今も I keep my eyes on you
そう手を引くよ 辛い思い出なら蹴飛ばして
泣き腫らした瞼なんて
気にならないくらい 君は綺麗だから
長い髪をかき分ければ 見えるはずだよ
いつも I keep my eyes on you
暗い夜に負けそうでも
導く僕が となりで笑うから
過去を抱いて凍る愛も 溶かしてゆける
今も I keep my eyes on you
Roomaji
shinya no kare no ME-RU nagamete tameiki no kimi
zurui owakare tatta hitogoto "sayonara" nante
kimi no techou mada kare to no yotei de uzumatteru
hontou wa boku no namae ni kakikaete hoshii
hora nakiharashita mabuta nante
ki ni naranai kurai kimi wa kirei dakara
nagai kami wo kakiwakareba mieruhazu da yo
itsumo I keep my eyes on you
kabe ni kizanda futari no namae kesenakutemo
ame ga nagasu yo yagate atarashii yume hajimaru
wasurerata tanjoubi mo boku to issho dattara
heta na uta de asa ga kuru made iwau no sa
hora kurai yoru ni makesou demo
michibiku boku ga tonari de warau kara
kako wo daite kooru ai mo tokashiteyukeru
ima mo I keep my eyes on you
sou te wo hiku yo tsurai omoide nara ketobashite
nakiharashita mabuta nante
ki ni naranai kurai kimi wa kirei dakara
nagai kami wo kakiwakareba mieruhazu da yo
itsumo I keep my eyes on you
kurai yoru ni makesou demo
michibiku boku ga tonari de warau kara
kako wo daite kooru ai mo tokashiteyukeru
ima mo I keep my eyes on you
English Translation
Late at night, you gaze at the message he sent you, and sigh
He cowardly sent only one word to you: "good-bye"
Your notebook overflows with plans you've made with him
To be honest, I want my name to replace the one you write
Come now, I can't help but be bothered
Because even when you're crying your eyes out, you're so beautiful
If you just raise your head, you would see that
I always keep my eyes on you
Even if the two of your names carved on the wall don't disappear,
The rain will pour down, and a new dream will start
He even forgot your birthday.
But if you were with me, we'd celebrate
until the break of dawn with my bad singing
Come now, even if it might seem like you'll lose to the dark night,
it's okay 'coz I'll be your guide and be by your side, smiling
And even your frozen love of the past will begin to melt
Even now, I keep my eyes on you
Yes, I'll lead you by the hand,
and kick away all of your bad memories
Come now, I can't help but be bothered
Because even when you're crying your eyes out, you're so beautiful
If you just raise your head, you would see that
I always keep my eyes on you
Come now, even if it might seem like you'll lose to the dark night,
it's okay 'coz I'll be your guide and be by your side, smiling
And even your frozen love of the past will begin to melt
Even now, I keep my eyes on you