Does the guy I love loves me back?

I know this guy who started something with me. We went out together for a few weeks. Then suddenly he change and does not treat me like before. I fell in love with him and now I am in pain/heartache. He makes me frustrate because I don't know what he is thinking. One minute he can be nice and the next be cruel or mean. He does not respect me or takes my feelings into account. Now I'm not sure if he still love me or does he has another girl?