I think a lot of people mix up lack of motivation to burn-out.
Lack of motivation is thinking about something and never even starting it.
Burn-out is when you do something full force, you get lots done in a short period of time that by the time a few days or weeks go by you simply exhausted yourself and cant force yourself to keep going the initial pace you started off with.
The best advice is take a good break away from it. Dont even think about it, and in several days you'll see yourself craving to dive back into it. And you'll regain your initial excitement again, and again you'll burn-out.
So basically you'll have to learn to work around in a cyclic manner and accept the fact that its ok, but in the end as more and more gets finished, before you know it you'll complete everything you wanted to.
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