Secret Agent Snape in OotP

[severusbook4]

No: HPFGUIDX 76532

This may have been discussed before, and if it has, sorry for double 
posting. In SS Quirrel talks of Snape trying to stop him from 
finding the SS and thwarting him in his attempt to kill Harry during 
the quidditch match.  He does this while Lord Voldy is attached to 
the back of his head.  Now my question is how is Snape going to pull 
off being a DE while he was actively trying to stop Lord Voldy from 
coming back to power in the first book?  Lord Voldy had to hear the 
conversations Quirrell had with Snape and Harry, and he is probably 
pretty angry about a former DE being against him.(serious 
understatement) IMHO I think Snape is toast, Lord Voldy is just 
trailing him on, until his usefulness runs out, Snape must be 
feeding him some information, just nothing very critical to the 
OotP, just enough to keep him alive.  What does everyone else 
think?  This has been bothering me after re-reading the SS.