Should I leave my boyfriend?

We have been going out for a year on/off. I left him back in December then went back because I missed him 2 months later. I'm 18 and hes 23. He doesn't work and sits with his friends all day smoking pot. I'll be heading to college in Nevada(we're on the east coast) in a year. I'm taking a trip over there this week. So we made plans to hangout a few days before, for the last time before I leave. At last minute he canceled and went on a camping trip with his girl friends, including a girl who has hated me since we started dating. She always says bad things about me and he even admitted that she said things while he was with her. He got very drunk while there and didn't bother calling and texting except for once a day for only a few minutes. This is not the first time he has ditched me to go hangout with his friends. And though he really seems like he means it when he tells me he loves me lots and wants to be with me. Its hard for me. My parents want me to leave him because hes constantly leaving me in tears with his choices. I can't stand the pot smoking/drug use and his lack of ambition to find a decent job. Especially when i'm such a career orientated person. I know i'm young and there will be others. But I guess I just feel lost right now. Help?