First off, you said you made it worse but that looks AMAZING! It looks very professional like something out of a manga
With that out of the way, yes, I used to be a bit like that but not as much anymore. I still struggle with things like essays where I finish the first draft but don't feel bothered to edit it. I get the feeling of having been super motivated, full of ideas when starting something but losing interest when coming back to it. I don't know how exactly to fix this commitment issue, but I have a few ideas to think about:
-My hobbies are primarily making video games and music, both of which take a lot of time for one project. And while I might be able to rush a song in a day or two, that always ends up in me noticing an issue and going back to fix it. In a similar way, with video games I'm constantly testing with friends and finding bugs, which force me to stay committed to the project. So, maybe if you went back to your drawings and simply look at them, you will start wanting to make changes?
-Sometimes I draw, and while I used to always finish it in one sitting, I usually take more time now. Perhaps it has to do with the process? If you have a specific idea for the entire drawing (being able to imagine exactly how it'll look), it's definitely hard to remember it all. In that case, you should start off with a general sketch, write down some of the ideas, or use a reference. (Honestly I think you're a better artist than me so I might be wrong)
PS How do you make such clean art? All my drawings feel like they have so many unnecessary fold lines and details and it looks messy