so if the line changes over night it's right??

Just would like to know if the line of a hcg test gets darker after it mean positive. When I took the test it was one dark solid line and then I felt like I saw thin line then thought nah it's a negative test came back in the Moring to show my bf and realized there is two lines one dark n one light. Can I trust it... need some serious answers. Here is the photo.