Day 8, 500+ words, learned 0 new words today, with low percent

What am I doing wrong with this program?
I'm on day 8, level 5, German.
Today although I've been through over 100 cards, I have learned 0 new words.
Also my percentage correct was low (in the 40% range).
I seem to be stuck on words I've been stuck on for days (although I am at level 5)
and today I learned no new words.
Am I doing something wrong with this? Are there just plateau days (this feels like a bad plateua, though).

You are working insanly fast! generally I am doing 150 new words per week, so of course the practice will be harder.

Let me clarify: prior to Lingvist I had done a lot of Rosetta Stone, Duolingo, Pimsleaur, Memrise, and Drops, so I had a lot of foundation to start with which is why I moved fast at first. But to have days with not a single new word added and pretty low percent correctness is a shock. I think I’m missing the gist of how lingvist works.

I think you are missing the gist of how SRS (spaced repetition system) works. If your correct rate is low, it either means that your memory is extremely bad (which is unlikely), or that you didn't learn the word properly on first encounter. You are supposed to put in effort in learning the word the first time you met it, its meanings, conjugations, and use cases, and connect it your existing knowledge about the language and the subject the word belongs to. You learn it on day one, form a firm foundation of the knowledge, and review it when you are about to forget it. You don't amortize your learning to future sessions, and hope that your understanding will grow as you see more and more of it.

I hope this is helpful because it's the mistake I made when I started using SRS softwares. If you want to know more you can check out the Twenty rules of formulating knowledge, number two of which is "Learn before you memorize".

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