It seems that you don't understand English vocabulary, ie when to use which words. English has many "layers" of words, with different meanings, and varying degrees of sophistication. "absent" means you don't show up for work or school, or a business meeting, somewhere you're supposed to be. What you have said means that the librarian did not show up for work, so your sentence just doesn't make sense. Even though some people would probably understand what you wanted to say, it isn't what a native speaker would say (though there may be variations in different countries/regions in the English-speaking world). "the librarian wasn't behind the counter" or "wasn't around" is what we would say in my country).
I've said it before and I'll say it again: TAKE ENGLISH CLASSES. I do not recommend trying to teach yourself a foreign language, especially by posting questions on here. You might make SOME progress, but it will be very slow. Why not just go take classes or hire a tutor? That's what they're for. There you will get the instruction, exercises & repetition that's needed to learn a language. People who try to teach themselves are the ones who make a ton of mistakes and never get it right, even after years of trying.
"storing" and "even though" (she was taking too long...) are also used incorrectly. Your speech in general is too formal. English speakers do not use such formal speech in everyday conversation, except to express a particular style or viewpoint.
· 1 month ago