How to make myself happy

Currently I am relying on my experiences with others to be happy. Without time with others I become very sad. How do I become happy, or at least prevent being sad without others. I don't want to become too clingy to my friends, family, or girlfriend as I don't know what that could do to the relationships that I have. I'm torn because I want to be happy now but I don't know if the means I have right now are worth using because of the Possible consequences.