I was suppose to have AF on Monday (the 19th) and on Thursday the 15th I started spotting. It is not unusual for me to start a few days before/after Glow prediction. I spotted for a few hours on Thursday, nothing on Friday and when I woke up Saturday there was some light discharge when I wiped but nothing since Saturday morning. I am cramping lightly but no other period symptoms. Could a period try to start but not come if I was pregnant?