Feeling a bit stressed as we're TTC pink and having trouble pinning down O. Last two cycles were 34 and 36 days. Today's OPK was negative as it has been all week. We've been releasing twice a day since CD18 and DH feels like he has nothing left now. Should we continue waiting or actually DTD every night just in case the OPK hasnt spotted O? Really need to conceive this month as my BMI is now 18.5 as I've lost 17lbs in two months. Thanks