looking for a room from middle June/July

Hey guys! My names is Madara, I am 20 years old, I come from Latvia and the past year I´ve been living in Madrid. I´ve decided to move to Barcelona around middle of June and I am looking for a cheap (300/month), centrally located room. (perfect would be gotico)
I´d like to share with mixed girls and boys, because girls only appartments tend to be too catty for me) and no couples please. I am a happy and chirpy person overall and I am quite easygoing. I don´t smoke, but I love animals so if you have one I don´t mind. 
Let me know! :)