我是你想不起的念念不忘
[wŏ shì nĭ xiăng bù qĭ de niàn niàn bù wàng]
Expresses an unspoken pain: 'I'm someone who you can never recall but keeps thinking of me.' This suggests a strong affection towards someone or something that, no matter how much you are missed, aren't remembered. Such kind of feelings would be bittersweet.