Hi, I know this sounds cliche but it really does just take that one phone call. Once you get that one offer, your entire attitude towards interviews, AC rejections etc changes. I did like 6-7 ACs before getting any success and it really tanked my confidence, until I got the call a few hours after my GDC final round. A few days later, I got rejected from Weil post AC, but my attitude towards rejection became much more "positive" (for lack of better words). My focus really shifted away from self-criticism and towards seeking feedback ASAP, reflecting on whether the firm was really right for me etc. So please do keep persisting - don't let the rejection affect your AC tomorrow.
If I may ask, which firm interviewed you? And are you by any chance on the Baker McKenzie AC tomorrow? If you are, then I'll see you there!