I’ve had regular periods every 28 days since having my baby 5 months ago and even though I’m exclusively breast feeding. I’m not sure if I’m ovulating, though. My last cycle was 23 days rather than the usual 28 so I started testing on cycle day 5. The second day of using it I got a flashing smile. I know they work since with my daughter I got four flashing then one solid and conceived her the day before the solid. Could I really be getting an estrogen surge that early?