I feel isolated...my so called 'friends' have ditched me...what should I do now?

My only suggestion to you is to quit being emotionally attached to these group of girls you initially made friends with when you got to the city. The second step is to try and find new friends. I know it's challenging, but it's going to be much better than hoping those girls will one day not hate you for no reason.The point is, some people will not matter to you at all when you grow up, and when you look back you'll laugh about it. Spot someone in your school who is approachable and make friends with them...you'll feel better and those other girls WILL know they don't matter to you anymore.