Breast milk pregnancy test

I heard you can use breast milk to take a pregnancy test so, I took one last night and it was positive. I have a two year old who hasn’t been breast feed for over a year so is it possible the pregnancy test is really positive? I took three urine pregnancy test and got a positive for all three but have been getting negatives since which is why I tried the breast milk. (Pic is of the test today and I will put of the test one minute in)