It's really hard to say! I'm sorry you are in limbo like this! Those symptoms plus late AF do sounds hopeful though.... all I can really think to suggest is to wait a bit more and test again :\(. Although the average pregnancy would have shown up on a test by now, sometimes the HCG levels do take longer to build up and it can take up to around 20 DPO to register on a test at the extreme end of the scale. Of course, as you say it could just be your body playing tricks though - unfortunately only time will tell!
Did you see this table before? You might find it useful:
http://www.betabase.info/showBasicChart.php?type=SingleGood luck hun, I really hope your BFP is just in hiding, but I hope you find out one way or the other before much longer.
xx