population

So I have a question ladies OK I downloaded this glow app and a friend of mine told me to download the Flo app so I downloaded both. So I logged my period in both apps I had a period January 17th-22nd  now both apps are giving me different fertile windows and it's really confusing me because glow say my ovulation window is from 30th -6 and the Flo app says 23rd- 1st Feb and I logged the same information and both apps so now I'm very confused. So me and my fiancé has just been having sex every other night.  Oh here's The ovulation calendar I got from google