Corpus luteum dip 5dpo

Ladies, this is my second cycle charting bbt. This morning I have a huge temp dip, way below cover line. I am 5dpo, so based what I was able to find online- it is a corpus luteum dip. Anyway, I have not had that last cycle, so I am not sure this is something normal for me. If you experience that, do you have it every cycle? Or every other? Or once in a while? Not really sure what to think... Any advice welcome!