Firstly...don't be so hard on yourself! You know I think that sometimes we get frustrated with our body because we want to have "the perfect chart". Before we started to chart, or even knew about it, we just figured whatever will be will be. If we get preggo then heck, looks like we got lucky. If not...well try again.
But now with charting it's amost like you understand yourself too well. You pay attention to every little sign and overanlyze every cramp. You lie awake hoping tomorrow your temp will rise, or stay up, or whatever. I think charting is awsome, but the drawback of knowledge is knowledge itself! KWIM?
At any rate, you should calm down. You already know thata stressing out and obsessing only leads to problems reading your signs.
You are totally NORMAL. And I think when we start charting, it just gives us ONE MORE THING to criticize ourself about. Chin up, lots of women have been in your shoes and still got BFPs! You will too. You just need to be patient. Try to look at charting as a way to understand yourself better rather than a way to get pregnant. That way, you take the pressure off.
And you know, if you are feeling really frustrated and upset, why not take a month off for a break from baby making and charting and just enjoy DTD for what it is between the two of you. And then take another go at it once you feel up to it
I hope this helps...You can PM me anytime if you need support!