interesting. I have had similar. I am now 4 days late also. I had positive OPK's but then got very sick (stupid virus and then secondary infection). When I was sick I had some spotting and cramping (I don't normally cramp). I've done 4 HPT's - all negative. No symptoms other than reflux and a couple of bouts of random nausea. Reflux I get from time to time so don't count as a symptom and the nausea could be because of my AB's.

So I share your frustration