CONFUSED ABOUT OVULATION???

Someone please help me understand my body!! Lol SO I had an IUD. Got it taken out on the 9th of this month and then had my period on the 11th. I have a pretty regular period (every 28 days, lasts about 4-5 days) so I should have ovulated around 14 days after the 11th and been fertile from about the 20th-25th. So far so good. Well Those dates were predicted by another app I'm using before i found glow. They predicted it based on data I entered from my BBT, period dates, CM and symptoms. Well I took tons of ovulation tests starting around the 22nd and haven't got a positive ovulation test yet. I've heard some people never get them and ect. So okay whatever maybe they don't work for me. So I tried to go off my BBT and it dropped real low to 97.0 on the 22nd and then went up to 97.3 over the next two days so I'm guessing I covulated on the 22nd but then come the 25th and 26th I drop down to 97.0 and 96.9! So now I'm all sorts of confused. And Today it's back up to 97.6! So this week I stared using glow and I entered all the data I had in my other app from the past three weeks in here. Well everyday I enter data glow keeps moving my fertile window farther and farther back. So it said Thursday was my peak ovulation day and then Friday it said oh wait today is and then today same thing! Now it's saying tomorrow is my peak day! So I'm even MORE confused! How the heck will I ever know if I'm ovulating or not??