Xinxin,
actually i strike accidentally.
that time my cycle super loonngg.. i took 3 times acupuncture until cd20, still no fish ball, opk neg. Dr.Tan tot maybe im not O that cycle. so im thinking to let go that cycle. i did not take opk or checking my temp again after that. only until my period have not come on CD42 (im still thinking maybe coz im not ovulating), i got that 'feeling' to check and found out that i got pregnant. after seeing gyne and check on baby size couple of weeks after that, gyne told me that i got late O on cd23. and me n my hubby remember that we did that on cd21 and cd24. so dont know which one is strike.
yenyen,
if im not wrong, chemical pregnancy is when your urine test shown positive, but there is no sac when you have scan. they r saying sperm and egg did met but did not grow to embryo and attach to the womb.
i use OPK that i bought from Dr.Tan. it is quite accurate for me.