Early period? Or...?

I had unprotected sex on 12/5 and I took an emergency contraceptive pill about 29 hours after the fact. I have a few period tracking apps because mine is so irregular. Yesterday (12/14) I noticed a little brown discharge, then later in the day when I wiped it was bright red blood with a bit of egg white like mucus, and today (12/15) there was enough when I wiped for a tampon - which after a few hours was almost halfway full with definite bright red blood and egg white like mucus. So I’m wondering, is this a good sign that I’m not pregnant? Is it just the EC pill making my period start early? My soonest projected period start date is 12/23 for reference!