fertile window question

I use 3 different apps to track different aspects of my fertility. one app said I ovulated on 13th, another says I ovulated on the 17th, and another app says I ovulated today 22nd. very confusing.. I just got off nexplenon in November and first period returned Feb 2-5. I noticed pink tinge and ewcm on the 12th. I also have ewcm and thick white lotion cm today but read that can be post ovulation estrogen increase or early. sign of pregnancy.. I haven't started tracking bbt yet due to unable to find a thermometer in store that does this function. the one I have only reads 3 digits. it's too late now to do opk so af is due Mar 2 if af doesn't show. I'm going to be more proactive with bbt and opk. anyone have any insight? I feel my ovulation was on the 13th too but I had sex everyday anyways.. thanks sorry so long!