How the hell do you edit a 70,000-word novel? I can barely do a 3,500-word short story

Several months ago, my teacher asked me to edit a chapter of a mythical novel that had been written by a girl on my school's creative writing team. <br><br>The chapter was 3,500 words. It was one of the most grueling edits I had ever done, and I ended up editing it for two hours (I'm an extremely picky editor). No joke, I had to stop every 50 words to take a break and clear my head.<br><br>Now imagine this on steroids. Most adult novels are 60-100,000 words. That's 16-20 times the length of that chapter. Heck, I would probably lose my mind if I even tried to do it. <br><br>I'm currently working on my own project, and it's about 40,000 words in. I haven't fully edited it yet, but I've done a lot of spur-of-the-moment editing in the past two months. I can barely even look at the words anymore, yet alone edit them. <br><br>When I asked my teacher about editing a full-length novel, she said she doesn't find it too bad. She had a 70,000-word novel that took her nine months to write, and when she started editing it, she did it in a month. And then when I asked her about edits for other novels, she said her friends had done things like spending 12 hours a day for three months editing their novel.<br><br>I'm wondering if I should drop the project because I know I'm not going to want to do that. And if I do drop the project, it's kind of sad to think that I'm just starting to get into my groove as an author, and now I'm already spending my time on projects that probably aren't going to end up going very far.<br><br>&#x200B;<br><br>tl;dr: How do you edit a full-length novel and not lose your mind? Did you feel like you're a completely different person by the end of it, or were you able to keep your head clear during the process?