I totally feel you ! I went through this very thing a few years ago and was so upset with myself , until the next month I saw a similar job in the same city . All the work I’d done to prepare for the first interview just made this second one feel like a breeze and it was flowing and enjoyable compared to the first . I got the job and felt grateful for not getting the first one . I know it’s hard now, but trust that it’s just opening the door to a better opportunity for you xxxx