YOU SAID:
i miss who you used to be
INTO JAPANESE
私はあなたが誰であったか懐かしいです
BACK INTO ENGLISH
I miss who you were
INTO JAPANESE
あなたがいなくて寂しいです
BACK INTO ENGLISH
I miss you
INTO JAPANESE
あなたがいなくて寂しいです
BACK INTO ENGLISH
I miss you
That didn't even make that much sense in English.