Searching for house in Rotterdam

Hello my name is Electra and I am an arch student from Greece. This fall semester I am going to visit Rotterdam (Netherlands) with the erasmus exchange programme but I'm a little nervous because I haven't found a place to stay yet. I'm looking for a small appartment or a dorm and I don't care about the number or the gender of my roomates as long as I have my on private room in it. :)