Toxic goals

I am one of the most disciplined people you will find around. I set goals. I make a plan. I work hard. And when I have setbacks I regroup, keep going, and work twice as hard. This is normally a good thing, but lately I've come to realize it is not such a good thing when working towards what I am going to call "toxic goals". I've had one of this for a while at work and slowly, but painfully, I am starting to realize I probably have to let go. I have worked hard. I have delivered.  I have requested and acted on feedback. But that is not enough. There are too many factors that don't depend on me and I can't control. I am getting disappointed, frustrated, and feeling taken advantage of. And that is not a good place to be. So it seems like the only way to get back in control is to do the unthinkable-for-a-fighter-like-me and just give up and move on.