Advice on AF and conceiving.

Emily
My last period was 8/14, 10 days after I spotted for 4 days. My period is now 9 days late. Took a test and BFN, I called my doc and she said tol wait until Tuesday and they'all have me come in. Last night after I went to the bathroom I wiped and seriously had like a tiny smudge of blood. Now I have nothing again. What do any of you think? Do you think I could be pregnant or something else is wrong?