please help!! any advice is nice!!

I was suppose to start af yesterday but I've just been lightly spotting..mostly a brownish color! I'm usually spot on when it's time for af but not enough going on to call it af...I put a tampon but when I go to change it it's like brownish clear snotty (tmi sorry!) discharge!! Any advice that it may be the start of af n she's just running late or could I possible be pregnant?!! Thank you!!