Positive test then a negative test

Brianna • Mon, Jun 26 • Recently diagnosed with PCOS; TTC #1 😇💜

I took a pregnancy test about a week ago and it came back positive. I went to the doctors 3 days ago and their test came back negative. I go back to the doctors this coming Friday (6/30) to get re tested. I'm really confused as to why it came back negative at the doctors but positive on my home pregnancy test. 😞 my stomach has been growing and I'm just confused. What does this mean?