使用了形容词短语 contrary to my heart 来表达违背内心，表达地道。
Fine, just this once. I stepped in resolutely, casting all my worries aside. But after so long, doing something so contrary to my heart left me feeling deeply unsettled. Like a thief riddled with guilt, I sat by the computer, gripping the mouse as I had desired, only to stare at the screen with a sense of loss; the images that once excited me now felt utterly disgraceful.
I realized my heart was racing wildly, filled with fear, with no trace of the joy I had expected. With trembling hands, I clutched the mouse—my only companion in that moment. I sat there, paralyzed in agony.
The phone in my pocket vibrated; I knew I had been caught. Despite my mental preparation, the feeling was just as intense as before—nervous and thrilling, yet this time accompanied by a profound sense of guilt.
To this moment, I still don't understand why a "repeat offender" like me would feel this way. Driven by a sense of conscience, I walked my way home. As the sun-drenched breeze brushed against my face, I felt no warmth, only a mounting, bone-chilling cold. The walk was incredibly arduous. I thought to myself, if only time could turn back, I would never do it again. But unfortunately, there is no undoing the past.
好，就这一次，我毅然决然地迈了进去，把所有的顾虑都抛在了脑后。但毕竟太久没有做过违背心意的事了，内心终究感到一阵阵烦闷。我像个做贼心虚的窃贼，坐在电脑旁，如愿以偿地摸着鼠标，却又若有所失地盯着屏幕——那些曾经令我激动的画面，此刻看起来竟是如此难堪！
那一刻，我发现自己的心跳得飞快，心中充满了恐惧，丝毫感受不到预想中的喜悦。我用那颤抖的手握住鼠标——那是此刻我唯一的依靠。我僵坐在那里，陷入了漫长的煎熬。
口袋里的手机突然震动了起来，我意识到自己被发现了。虽然早已有心理准备，但那种感觉依旧如往常一般——紧张、刺激，只不过这次还多了一份罪有应死的沉重感。
直到此刻我仍不明白，作为一个“惯犯”，为何还会产生这种羞愧感。由于良心的谴责，我一路走走停停地走回了家。任由阳光夹杂着微风拍打在脸上，我却丝毫感觉不到阳光的热度，反而愈发感到寒冷，骨头仿佛都冻僵了。这一路走得十分艰辛。我想，若时光能倒流，我一定不会再犯。但这世上终究没有后悔药。
"After a period of internal struggle I took my cousin back to the toy store"
"The reason we feel mentally exhausted is persistent inner conflict."
"My emotions were extremely complex and filled with inner turmoil."
"I know the outcome, yet I still lose to my own unwillingness."
"While walking, my mind was in turmoil, struggling with indecision."