Knocking from Under the Bed After a Talk with the Librarian

My most mystical story happened when I was about 16. I went to a school with a dormitory for students, but I was a local myself and could spend the night either at home or in the dorm, as I liked. Despite the school's physics and math focus, we had an absolutely unhinged librarian who wouldn't lend out The Master and Margarita because it was devilry, and kept pushing all sorts of lives of the saints and stuff like that on everyone.
One time we came to the library with my classmates, the boys started arguing with her about atheism, and she told us how once a student had complained to her that in the dorm the devils wouldn't let her sleep - they were knocking from under the bed. But the brave librarian came, sprinkled everything with holy water, and since then nobody bothered the student's sleep.
We took the books we needed, plus some pamphlets with prayers as a bonus, had a laugh and went our separate ways.
That night I was sleeping at home, but of course something started knocking from under my bed. The first time was right in a hypnagogic state, but the knock was very loud and very physically palpable, like the bed was shaking. I woke up, got scared, but stayed skeptical, but the second time this knocking repeated outside of a "falling into sleep." I felt insanely uneasy, I was too scared to look under the bed; I lay down the other way, head to the other end of the bed. I waited some time, maybe two minutes - it was quiet. As soon as I calmed down and chalked it all up to glitches, the knocking from under the bed happened again; even stronger than before, with the feeling that it struck right through the mattress into my chest.
Well, this is something, I think. And in a whisper I said "if there's any kind of unclean spirit and there is a god, then please, deliver me from this creepy stuff that's happening, thanks in advance"
And nobody and nothing knocked anymore.
You should talk less with Orthodox old biddies - you'll sleep better, that's the moral