First 2ww and already going bananas

This is the first month TTC, and for the first time since I got off the BC 4 months ago, I can't tell when I O-ed! How frustrating!

For the last four months the CM observations gave me the same signs of O as the position of the cervix and its firmness. The more CM, the softer and higher the cervix. Once the CM dried up, the cervix followed (went down and became firm again). All nice and clear for 4 months.

And than we decided to TTC. Since I never really observed the hard core eggwhite-like stuff, I decided to try Mucinex (see my previous journal entry). And that's where the troubles started.

I used an OPK on Sunday the 13th and it was positive. This would suggest that I will O on Monday or Tuesday (24-48 h later). And that's when the CM seemed the most fertile. But it wasn't any more eggwhite-like as usually, and it was definitely not as much of it as usually. And then it totally disappeared. So I thought I Oed during those days. BUT my cervix stayed low and soft for the next 2 days or so, which would indicate that I O-ed on the 17th! But by this time I had no CM at all.

So the question is, when did I O? On the 14/15, as the OPK and CM say? Or on the 17th, when my cervix seems to indicate? Am I 7-8 DPO or am I 5 DPO? Or did I O at all??

I have so much to do at work, but I can't get my mind off this subject! I want to POAS, but if I'm only 4 DPO, I know it won't show anything even if I turned out to be pregnant later on. Thank goodness I don't have any HPTs; I won't purchase one until I know it has a chance of showing something. But I can't wait another 10 days or even a week! I need a shot of sanity please!