25 years old, looking for shared accomodation in Prague

I am coming from Slovenia to Czech Republic for internship and writing a master theses at the Faculty of civil engineering of the CTU in Prague this October and I expected a room in a students dorm, but it seems, that they are full. So now I must find a place to stay there for three months, because everything else is already prepared for me and I want to actually come. I am looking for something cheap, also shared rooms and shared appartments. I am easy going and calm. In Ljubljana I live in a student dorm, so I am prepared for almost everything :)