Can I still find forgiveness for wrongs done in these blessed days?

Salam alaikum. I’m really shattered inside. For the last four months, alhamdulillah, I managed to stay away from many sins. There was one in particular that had always been my biggest struggle, and I left it too for those months. I don’t know what happened-maybe it was shaytan-but lately, resisting it became so hard, and I slipped a few times. Each time I cried and repented, but now I fell even deeper. The idea that sins are magnified in this sacred month is crushing me. I feel like I broke my word to Allah during such a blessed time, and I’m terrified He won’t forgive me. I’ve been giving a lot in charity, hoping it shows my true regret. In these past months, Allah felt so close-like my dearest confidant. But now that nearness feels like it’s fading. I truly intend never to go back to that sin. I’ve prayed extra rakats, given charity, yet I still feel I’ve ruined myself in these precious days. With the Day of Arafah tomorrow, I’m so scared my duas will go unanswered. I’m just heartbroken. Any guidance would mean the world. May Allah grant you goodness. Jazakum Allahu khayran. Walaikum assalam.