I have polycystic ovary syndrome (PCOS) and have been receiving treatment from a local doctor for the past month. I recently took a pregnancy test, which showed one dark line and one faint line. However, when I tested again the following day, only one line appeared. I then underwent an ultrasound, which did not detect a pregnancy, but my endometrial thickness was measured at 14mm. Does this mean I could be pregnant despite the ultrasound results?