Different ovulation days and when I can get pregnant?

So..

On all of my apps it is saying I have different ovulation days. I am currently using the Clearblue Advanced fertility monitor to track my ovulation. I started testing on the 12th which showed a low result. I received a “high” result on the 19th and 20th and am waiting to test today.

I don’t really know how accurate this monitor is

My Flo app is saying i ovulated on the 19th.

My Glo App is saying I ovulate on the 21st

My Premom is saying I ovulated on the 20th.

My PC app is saying I ovulate tomorrow.

There’s just so many results. I’ve gotten high but haven’t got a peak as of yet. I’m worried I’ve missed my chance if my Flo App is correct.

I wasn’t able to have sex on the 19th or the 20th. Worrying I’ve missed my chance…

I am currently feeling cramps, and today I have experienced a lot of discharge.

I also am just wondering how long after you ovulate you can get still pregnant for.

Thanks.