Day 21 & 28 bloods

Lo

Been ttc for over 2 years now. Started my first course of letrozole last month at 2.5mg day 21 & 28 bloods confirmed no ovulation!

2nd month 5mg day 21 no ovulation, got day 28 yesterday which shows ovulated!

So my question is..how common is this? Is there still a good chance i could get pregnant thus cycle? (Had intercourse 2 times between each test). & when would i likely have ovulated?

When should i do a test?