J.S.
You really need to add more details to your question and add some punctuation. Punctuation can change the meaning of a sentence. Did the lines disappear after two days? Or did you take another pregnancy test two days later after the doctor took a pregnancy test?
Did the doctor tell you that you're pregnant? How long after did the lines disappear? Two minutes? Two hours? A while after the urine test, the lines can change how they look and aren't reliable any longer. That's why the directions say to read them within a certain time frame.