Relationships are important for good mental health.  Look around and ask yourself about the quality of your relationships (you become like the 5 people you spend most of your time with).  If these people don't represent what you want then you should make some changes.  

Special note - if you don't seize opportunities to meet new people, you are missing out.  One of the most influential people in my life was a chance meeting.  I was in graduate school and began cleaning houses for extra money.  I put an ad in the newspaper (long time ago) and a very interesting man answered my ad.  He initially acted really different and I almost turned down the opportunity.  My intuition told me that he was alright so I took the job.  He was the kindest, most gentle man who taught me so much about life.  He was dying as he waited on a lung transplant but he was SO ALIVE!  We talked the entire time I cleaned as he was lonely and would follow me around and fill my day with joy, wisdom, friendship and unconditional love.  I looked forward to cleaning his house.  He helped me to see that I was not as happy as I deserved to be.  He taught me how to reach, believe and dream.  And...he told the dumbest jokes that would make me giggle endlessly (even hours later).  He helped me to accept loss by embracing what I had gained.  He helped me grow in so many ways - all because we both took the chance.  

Take the opportunity to know the cashier at the store, to share a kind word with the lady at the restaurant, to talk to the mailman, to do unto others as you would have them do unto you.  No man is an island.