In reality the only person who can answer that is the Landlord.
He can either agree to re~instate the original Tenancy (to Nov 2010?)
OR
if he is feeling awkward let you have a new tenancy which would take you up to May 2011(that is assuming the new tenancy to be 12 months as well).
Quite frankly it would be to his benenfit to allow you to just stay on as if you had not asked to end the tenancy early.
However,as I say,it's up to the Landlord really,and it's best to keep on his side by consulting him over this;but he has the last word on this so try and keep him happy!
Good Luck.