My Landlord lives downstairs from me, can he move out without telling me?

Ive been living in my upstairs apartment since March, I signed a year least, my Landlord & his family lives downstairs from me. Yesterday I saw a moving truck outside, I thought it was for the people next door. I went to work & when I came back the downstairs apartment was vacant. Also after moving in, I notice that my landlord & I share a mailbox, I dont have my own mailbox. I dont think its an apartment, I think he build my apartment out of the attic. Why didnt he inform me that he was moving? Does my Landlord have a right to do this?