Just A Remider
Just a reminder to not push your self to much. If you want to keep learning a language then go but if you are forcing yourself to do it and it feels like a chore it's ok to take a break. :-)
I might springboard off of this and suggest that, in such a situation, one might even just need a break from using Duo.
Vary your sources of language learning. Read (or perhaps also listen to) a story or news article, find a podcast, listen to music, watch a movie or series. Try your hand at writing a story or journaling, find someone with whom to engage in communication.
If language acquisition feels like a chore, take a look at whether you're treating it like work. Find something fun in it, some method through which to engage.
The process will turn out to be less of a grind, and your progress and capabilities will benefit greatly at the same time.
Break the monotony and search for the joy to be found in learning a new way to express yourself, take in and think about the world around you.
Learning at a slower pace with more outside resources and a greater exposure to other media is good, in my understanding.