From one monkey mind addict to another, I've found this book and particularly this passage helpful:
Ezra Bayda, 'The Authentic Life' wrote:The third major obstacle we encounter on the spiritual path is our deep-seated desire to feel a particular way, whether it's calm or clear or spacious or simply free of anxiety. This obstacle is so universal and so deeply entrenched that we are guaranteed to get stuck in it again and again. In fact, whenever we feel frustrated in any way, if we simply ask, "How is it supposed to be?" we'll see that our discomfort is based, at least in part, on the entitled belief that we should feel different, namely better.
Probably all of us share in the illusion that if we practice long enough and hard enough, we'll get what we want -- enlightenment, good health, a satisfying relationship, or whatever else we're seeking. The hope is that in getting the reward, we will then feel the way we want to feel, and be happy.
We can tell that we're still harboring this illusion if we believe that not feeling good or experiencing distress means that something is wrong -- or even that something is wrong with us. This persistent belief drives us to do whatever we can to alleviate our discomfort. We think if we just practice harder, we're sure to feel better. We should never underestimate the extent to which we equate feeling better with being awake. But a key point about spiritual practice is that we don't have to feel any particular way.
Also don't be afraid to begin your session with mantras such as manis or the nembutsu, or whatever may help you relax or at least put you in a more receptive state of mind to what's going on right now.
The nembutsu specifically has helped me no longer be so distressed and "nothing works" about my practice and the restlestnsess.
You may also benefit from the perennial classic "Opening the Hand of Thought" by Kosho Uchiyama which helped me clarify greatly just how much practice includes.