Could blood withdrawal cause negative pregnancy test.

Okay ladies I have a weird question. Friday I got a vfl on Frer. Line got little darker on Monday morning. Monday afternoon I went to RA doctor and had a lot of blood taken for test (6 vials, and three smaller vials). I had a four hour hold, came home to take a test and the frer was negative. No line. This morning at 3:30 am took another one, and faint line again (about six hour hold). I got back up a little before 8:00 am and the test was a little darker than the morning- almost as dark the first time I took test.

So my question could blood withdrawal effect the urine test or is this a chemical pregnancy? I plan on testing later today and tomorrow but I am so confused. I braced myself for a chemical but now I’m wondering if it’s not.

I’m also calling Dr later today to see when I can get in.