One of the girls in my mum's group is 10 weeks pregnant with a 'miracle' surprise #2 bubs Her DD was IVF so I have everything crossed for you too and will be stalking for more news tomorrow but I did find this on the POAS website (hopefully your test is correct though!):

31. Can I use an expired test? No. The chemicals used in HPT's deteriorate after awhile and no longer function properly. This can cause a totally defective test (no control line), a false positive, or a false negative. Your best bet is to use a newer one!