愛の病 Ai no Yamai

Loving you, and loving you from the bottom of my heart...

好き and 愛 are not exact synonyms, so putting them together strengthens the feeling. 心底 means "from the bottom of one's heart."

...I learned that it could be something this painful...

ものなんだ is explanatory: "it turns out to be this kind of thing." It sounds like the speaker is learning something the hard way.

...I cried, stifling my voice.

声を殺す is a set phrase for making no sound, especially while crying. It is stronger than just saying "quietly."

Because of this encounter, my body...

出逢い is a more marked spelling than plain 出会い and often feels more fateful or literary. Mentioning the body makes the change sound physical as well as emotional.

...would go on changing like this...

〜てゆく suggests change continuing from now on. Again ものなんだ gives the line an explanatory "so this is how it is" tone.

...and I smiled, feeling shy about it.

照れくさい means feeling shy or self-conscious in a tender situation. It is a softer word than plain embarrassment.

If tomorrow you were gone...

いなくなる is broad: disappear, leave, or simply no longer be there. That vagueness makes the fear wider than a single concrete scenario.

...and the day after tomorrow your feelings changed...

心変わり means a change of heart, especially in love. Moving from tomorrow to the day after tomorrow makes the worry feel like it is spiralling forward.

...and someday you came to hate me...

嫌いになられる is passive from the speaker's side: "to be come-to-hated." The trailing dots leave the sentence unfinished in a nervous way.

Please get rid of these needless thoughts of mine right now.

余計な考え means unnecessary or intrusive thoughts. とっぱらう is blunt and colloquial, like sweeping something away.

You do not even have to promise that you will never let go.

離しはしない is an emphatic way of saying "won't let go." 〜なくてもいいから softens the request on the surface, even though the line is really asking for reassurance.

On nights when anxiety keeps me from sleeping, please stay beside me.

不安で marks anxiety as the cause: she cannot sleep because of it. 隣にいて下さい is grammatically simple but very intimate.

Please do that tonight.

今夜 pulls the whole request into the immediate present. The speaker is not talking about some future arrangement, but about tonight.

This love-sickness that will never be cured...

治らない makes the illness metaphor explicit. 永遠に makes it sound permanent rather than temporary.

...bringing tears, loneliness, and happiness...

The line simply lists 涙, 孤独, and 幸せ together. Grammatically they are treated as part of the same package.

...and made me into an adult.

大人にさせる is causative: "to make someone become an adult." It suggests being forced into maturity by experience.

Even if that world were something stained or dirty...

汚れた can mean morally or emotionally stained, not just literally dirty. That makes the word harsher than a neutral description.

If only I have your smile...

さえ often means "even," but here it has a limiting sense: your smile alone would be enough.

...I feel like I could keep going and do anything.

やってゆける suggests managing to carry on, not just doing a task once. It is about continuing from here.

"If tomorrow you were gone...

The quotation mark turns the earlier fear into reported thought or speech. It is no longer just floating narration.

...and the day after tomorrow your feelings changed...

Repeating the same line inside quotation marks makes the worry sound rehearsed, as if the speaker has gone over it many times.

...and someday you came to hate me?"

This time the fear appears as a quoted question rather than trailing off. That makes it sound more pointed and explicit.

If the words I just said were wrong...

としたら introduces a reflective hypothetical: "if it were the case that..." The speaker steps back and evaluates what she has just said.

And if what I am thinking right now were right...

These two としたら lines balance each other: maybe her words were wrong, maybe her thoughts were right. The grammar shows hesitation rather than resolution.

Each time, I want you to scold me right away.

その都度 means "each time" or "whenever that happens." いてほしい expresses what the speaker wants someone else to keep doing.

I want you to hold me right away.

叱って and 抱きしめて are very different verbs, so putting them side by side makes the request sound unstable: rebuke and comfort are both being asked for.

Please get rid of these needless thoughts of mine right now.

The line returns almost unchanged. Repeating the same wording matches the repeated overthinking described in the line itself.

You do not even have to promise that you will never let go.

Because the line returns again, 約束しなくてもいいから starts to sound less like calm softening and more like repeated pleading.

On nights when anxiety keeps me from sleeping, please stay beside me.

The words are simple, but repetition makes the request heavier. The speaker keeps coming back to the same need.

Please do that tonight.

Again 今夜 narrows the focus to the present moment. It interrupts the larger future fears with an immediate request.

Loving you, and loving you from the bottom of my heart...

Returning to the opening line makes the ending circular. Grammatically the song comes back to the same starting statement rather than moving somewhere new.

...I cried, stifling my voice, because I learned it could be something this painful.

This last line compresses earlier wording into one sentence. That kind of compression often makes an ending sound like a summary or conclusion.