Sometimes we falsely equate accomplishment with happiness, but have you ever accomplished something only to be void of happiness altogether? I have to say, if there is any causal relationship at all, for me happiness is much more likely to produce accomplishment than the other way around.
I've found that when I focus on creating peace and happiness within, the
things I want to accomplish have a much greater chance of manifesting.
By not focusing primarily on what I want to accomplish, opportunities
naturally arise for me to accomplish those things. Things happen when I'm busy
doing something else, when I'm busy taking care of myself and not forcing my will. Things happens when I'm focused on trying to create inner peace and attempting to do the right thing.
This may all seem paradoxical, but often that is what truth really is. For instance, isn't it often true that when we slow down, we actually tend to
accomplish much more? Why is that? It is because we are not propelled by self-will. When we stop trying to force things and selfishly grasp for things, they happen.
So if happiness and accomplishment are two different things, or rather, two separate pursuits, which would you rather have? Don't worry, they are not mutually exclusive, so sure you can have both, but one may have to come first before the other ;-)
The point is that if your primary focus is on accomplishment but you continue to live in great angst and unease, try letting go and see what happens. I'd personally rather be happy and have peace than accomplish all kinds of worldly nonsense, if I had to choose. Sure I would love to accomplish certain things but having suffered emotionally and knowing how agonizing that can get, I would never sacrifice my peace for a few toys or some recognition.
The irony is that by pursuing happiness, the accomplishments accomplish themselves.