I live in Torrance, California, and I have a room for rent in a house.  There are a total of four people living on the property; myself, my landlord, and two other tenants.  

In passing, I had mentioned to my landlord that I'm going to start looking for a place for me and my girlfriend, but I did NOT give him written 30-days notice (it's a month-to-month lease).  But he started looking for a new tenant already and found one.  This tenant is going to move in on June 1st, I will take my landlord's room, and he will live in his trailer in the driveway.

But I don't want to move into his room!  He has no intention of moving any of his stuff out and I have to move my stuff in!  It's going to be completely cluttered!  I've been beating my head against a wall to find a place, but I don't know if I can do it before June 1st.

What can I do in this situation?  What he did was illegal, right?