Unfortunately hun our bodies seem to play lots of tricks on us around tww time either that or it is us being extra sensitive to each and every little niggle that maybe normally we may not have noticed - sure fire way to send us crazy! I think you are right to test again tomorrow with FMU and see what happens definitely not out yet you could have a late implantation (maybe could be why you have had some blood). Are you having an official blood test this week?
AFM - Still waiting to start next IVF cycle, spoke to the nurse this week about a plan. They are going to treat me for natural killer cells this time also as my levels were slightly elevated back in October and they are not going to risk my pgd tested embie. Will be having the endometrial scratch repeated before I get started as well.