Fortunately, the Buddhist notion of “non-attachment” can be used as an alternative. The moment we start falling into the discouragement spiral, by wanting get motivated we end up doing the opposite: we just let it go. We take distance, we clear our minds, we do something else, we try to remove the novel from our mind. This break should last as long as you need it to, so that you can detach yourself from all the negative emotions and sense of urgency in achieving your pre-set goals.
It is important to have a clear vision that we are writing because we are passionate about it.
To be honest, there is always a reason for lack of motivation, and this doesn’t always reside in writing. The passion of writing depends on the balance we achieved between our life and our writing. If you feel this has become an obligation, then you won’t enjoy the project. Try to be kind to yourself, and ask yourself what would you do instead of writing (as you are blocked) and act accordingly. You might need to solve an issue on your daily life in order to fully enjoy writing.