Does anyone have experience with having positive at home tests, then having it negative at the DR?!

I have 5+ faint positive tests. This mornings was still faded but clearly visible.

When I went to the DR today she said her test was negative, so she pulled me out of the ultrasound room and sent me for bloodwork... I did a blood test today and will do more on Thursday.

Am I having a chemical pregnancy?! My period is 3 days late.. and I swear there’s lines on my Pregmate brand tests.