Hi,
I moved in here about 3 months ago and need to move. I had a 1yr lease agreement, but...

Before I moved in, I signed a lease agreement for the bigger room. I found out the day I was moving in that the room was rented after I signed the lease. The landlord never drafted up a new lease for the smaller, cheaper room which I am currently renting. If I move out, would I be breaking a lease or is the lease null and void because it is not the room I am currently renting?

You in effect ratified the change in the lease (so as to take the place you are in now) when you moved in without objection. You are bound by the lease.

Agreed, you could have voided the lease, by not accepting the change, but once you agreed to move in, you are now bound by the lease.

Is he still charging you for the larger room?