I am 25 yrs old and trying to conceive. Just started charting this month, but have been using OPK for 2-3 months. Usually i stop using the test the first time its positive. This month, i started the test from day 11-19. on days 16,17,18 it was positive. My BBT went high before first +ve day, and low and high and low alternate days. I'm not relying on BBT alot as i'm not sleeping right. Now i dont know what to understand if OPK is positive on 3 days of the cycle. How do i interpret it ? We had sex on days 13,14,15,16, but not after that. Is it possible for me to conceive ?