OPK frustration

I have been using wondfo OPKs for the past 4 months ttc. This is the first time they have all look almost the same even though they are from a week and a half worth of testing at least twice a day. I have been drinking a lot more water this cycle so could that be why there isn't such an obvious +? SO and I have been BDing everyday just to make sure but it's no fun having to guess if I've actually ovulated or not! I wish we had a bell or something go off the moment it happened so we knew! Lol