17DPIUI BFN NO AF

Im super confused right now with my cycle, I have 31 day long cycles, this mth I did letrozole from days 3-7 and then confirmed ovulation on day 14 and IUI that same morning, I then took progesterone suppositories for 12 days after and then 14DPIUI I had pregnancy bloodwork which was Neg. That same day I had a small amt of pink spotting when I wiped so I thought AF was coming but it stopped after thar wipe and no sign of AF Im 2 days late and still BFN... any idea whats going on if I could still be pregnant?? Help!