could I be pregnant

Mary
I was supposed to start my period on April 27th but I was 3 days late and had a light brown flow I guess u would say but only when I wiped so I took a pregnancy test and it came out negative had the same "flow" for the next 3 days with a light pink spotting now it stopped can anyone tell me what's going on I called my OB and she said to wait a couple more weeks