Please help with my very big dilemma?

I really am having to choose between a career and my friends. Whilst in uni, i had a part-time job stacking shelves, the work was rubbish but i made friends, great friends! I'm someone who struggles to make friends and is often afraid to go out, so these friends really do mean the world to me. However, i have graduated uni and i have a graduate job. Even so i have maintained my part-time job alongside. Why? because as much as i like my graduate job, everyone i work with is some 30 years older and so i'm not making any friends my own age. Therefore i keep my Part-time job on the side for the sake of having friends. But it's starting to really take its toll! Working 7 days a week is exhausting and wearing me down. My parents have insisted i should give it up because there is no way anyone can go on and on working 7 days a week indefinatly, i have to give it up. But if i do i lose all my friends, and i can't give up my graduate job as i don't want to stack sheleves all my life. This is what i mean when i feel like i'm being forced to choose between my career and having friends. HELP!?