Hmmmm. Answer please

Mrs. • Finally have our babies. R.I.P Kimara Jeffers. Welcome 2 handsome boys Allan and Kayden Jeffers. 👧🏾👼🏾👶🏾👶🏾👦🏾
Ok. I'm confused I took an ovulation test and it came POSITIVE. So I took one just the hell of it and it came out NEGATIVE. Why is that??