Your purpose in life is to glorify the Lord...that's the purpose of everything really. Friends are difficult to find at any age, believe me. I've been betrayed by friends and stabbed in the back, but the Lord has shown me that He's always there for me and that He is the friend that sticketh closer than a brother. If you're sad or lonely, I would recommend that you seek out the Lord. Do you have a personal relationship with Christ? Also, I would pray for yourself to have the Lord send you the right kind of friends. I did so at one time in my life and the Lord has given me so many good, decent friends that I don't even know what to do half the time! I'm so thankful for the Lord answering my prayers and giving those people to me in my life. He'll surely do the same for you. However, I would recommend, since you are so young (and even if you weren't), do NOT look for friends on the internet. There are a lot of people on the internet who could potentially harm you under the guise that they want to be your friend.

May the Lord keep you safe and may He bring you true friends in your life.