Re: Do i have ADHD?
That sounds a lot like ADHD. I would make an appointment for testing. Ideally you want to see a psychiatrist who treats adult ADHD a lot, but if you have a family doctor you trust, that would be a good place to start.
The good news is, if you have ADHD, there are medications that can help. The bad news is, it is a lifelong problem, and the medicines will only help, not erase it entirely. There are non-drug techniques that can help. In your case, pacing seems like a good start. Taking on manageable tasks, and finishing them.
Believe me, I get it. I set unrealistic goals sometimes, too.