Ask HN: How the hell do you stay organized as a dev?

I think of myself as reasonably competent and intelligent. I have seven years of experience. Recently I was given a task I've wanted to do for my entire career, which was being in charge of a greenfield project from the ground up that, most importantly, is not a web app. I was so excited to dig in and get away from front end development and learn a new set of skills. EOQ is next week and I'm worried I'm going to blow the deadline. This isn't the end of the world, I'm not going to get fired, but it's not great for my reputation and catastrophic for my ego. I'm looking back and trying to figure out what I've been doing wrong.

Why didn't I ask for help? Day to day, I didn't really see anything wrong. Things were progressing. One red flag that I ignored was that my manager, who I have a good relationship with, was getting on my case for not staying on top of my tickets. I wasn't updating them, I wasn't adding more when it was necessary. I just find that I go blank when I try to organize a task, especially one as large as this. I don't know how to break them down. I had an idea of what tasks were remaining, but it was just in my head. I hate--HATE--adding more points to a ticket because I feel like it makes me look incompetent as it grows and grows. At some point you're supposed to break down tickets like that, but I'm all but incapable of breaking a task down. It's either done or its not. This results in giant PRs, shambolic commits, scattered debug crap. Overall good code, I'm told, but messy sometimes.

Why didn't I ask for help? I was doing a lot of new stuff, and I learn by doing. I need to suffer at the hands of the task or I'm not learning. There's a limit to this, I know. You can only spend so long on it. I don't know where that limit is.

Why didn't I ask for help? Pride. I wanted to prove myself. I'm on a new team with people whose technical skills, depth and breadth of experience, and ability to reason about software I greatly admire. I wanted to show that I could handle a project like this, so I'd get more in the future.

Why didn't I ask for help? Where's the line between seeking help and having other people just do your job? I don't know!

So I was humming along, flitting from one problem to another, and now the deadline approaches and I don't have functioning software, I have a pile of sorta kinda there code.

Possibly relevant, possibly not, is that I was diagnosed with ADHD a few months ago. I've always known that I'm scattered and have a hard time staying on task and being motivated, but I have a job and a family, so I wasn't so dysfunctional that I couldn't participate in society at all. I got this job, after all. I'm doing okay. I knew I could be more productive, I just didn't know how, or chalked it up to requiring more willpower that I didn't have. Anyway, post diagnosis I've been working on things and it's been helping. No magic bullets, but I'm less scattered overall.

If any of this rings a bell, and you've found solutions, I'd love to hear them.