EWCM but negative OPK

Jasmine

So I’ll start off by saying my cycles are pretty regular, I usually ovulate around CD 18/19. OPK show negative but I can see a line and EWCM is present on day 18. I’m on CD 16, OPK registered 0 as there is no line visible. I do have EWCM today and nauseous. Yesterday I had low reading of 0.29. What is going on?! Picture for reference of last cycle to today

This was November cycle which was put off due to getting the vaccine.