Why did my LH surge only last a short amount of time? I tested with OPK this morning and it was negative, tested again at 130 pm and I got a positive digital OPK, then tested tonight with LH test strips and another digital OPK and it was negative. We didn’t have sex until tonight after seeing negative OPK. Did I miss my surge? Will I still have good chances of pregnancy since we didn’t have sex until tonight?