Being in your feels means that you have a strong emotional reaction (often that emotion being sadness/feeling empty) to something that happened of that has been said.
Song lyrics are meant to be creative, and as such many people have little or no knowledge of the phrases involved. That's especially true, of course, if they are unfamlliar with the singer/songwriter.
In my opinion good song lyrics are a kind of poetry. The singer-songwriter Tom Waits has always billed himself as a poet. Some songs even began as lyric poetry as I pointed out here:
That being the case, such threads belong here in the Poetry, Prose and Songs forum, lest learners think the title phrase is something they should be using in their everyday conversation.
That being the case, such threads belong here in the Poetry, Prose and Songs forum, lest learners think the title phrase is something they should be using in their everyday conversation.
This question has nothing to do with song lyrics or poetry. The phrase in your feels is slang, which just happens to have been used to name a playlist. It really ought to go in the slang section.