can i trust clearblue digital opk??

hi girls without boring you all too much with my story but i am wondering have many of you got a smiley face on these tests and not ovulate? i got one on cd 13 9pm time. was negative the next morning at 8am. usually i get positive for two days. also cd 13 is early for me. but i have been getting accupuncture to shorten my cycles, i have had ewcm for the past few days and some cramps and that. i usually do around ovulation. I suppose i am just doubting things because this could be my first 'normal' 28 day cycle if so since my mc last sept didnt temp this month - drove me and dh mad last cycle any comments are welcome

hi Princerio, I didn't use clearblue digital opk's but used internet cheapies. I got a positive on the Monday at 11am and again at 4pm. It was negative by 9 pm that night (and yes I was a pee on a stick addict!) So my surge only lasted 12 hours max. I also should point out that we dtd that day but not after that- going by my ultrasound dates we conceived that Friday. Don't know how exactly that makes sense but that's what happened to us. Moral of the story is keep going for a week after a positive opk because you never know!