My Doctor Got me Confused

Je

I had my period Oct 23rd my cycle are about 35 length My doctor told me to have intercourse on the 4th which is CD13 7thCD16 & 9thCD18 to get pregnant. A couple day ago she told me the 3rd,5th & 7th. I really dont want to miss my OV days. I've been using Clearblue Advanced OV test every morning but I keep getting Flashing 😊 for about 8 days not counting my period days. Now starting to think its a waist of time. What should I do??