Check out student clubs, exercise classes, volunteer opportunities. Set aside time at least twice a week to be with a friend. Be open to different kinds of friendships. Not all of them need to be based on a deep, emotional connection. You might have exercise friends with whom you enjoy lighthearted conversation.
Some friendships last only a little while, perhaps just the duration of a semester or class project.
Others friendships you make at Cal may last a lifetime. Let close friends take care of you. Allow yourself to be vulnerable and receive help and emotional support from others. Enjoy online and email friendships, if you wish. There is no substitute for conversation and affection from a friend sitting next to you.