Has Voldy "used" a Horcrux?

[melhersheybar]

No: HPFGUIDX 133475

Here is a question I have been wondering about as I have read 
discussions about the Horcrux's creation and timeline.  Do you think 
it is possible that VD has already "used" one of his Horcruxes?  I 
mean, when the AK rebounded in the Potter House, something kept him 
alive - that something was the fact that he had gone farther than 
anyone else to make himself immortal by creating the Horcruxes.  So it 
seems to me that in order to be the half life he was for so many 
years, he would have had to get to one of his Horcruxes to release 
that piece of his soul to keep himself alive.  So, what was that 
piece?  Where was it?  Did he create a replacement one later or are 
there really only five left?  

Mhersheybar