How Can Depression Caused By An Obsessive Relationship Be Managed?

Sir, im 26yrs old, a marine officer from perinthalmanna. I'm more on the soft side and was not having any close friends till 12th. When i went for sea training, i got my best friend there, to whom i got too close. For not being bold, he used to fight with me and would stay away and avoid me often, which may extend upto a week sometimes. This continued for years.. Now im having one more close friend. But i'm always afraid of loosing this new friend. I cant talk or message him freely. I love him like my elder brother. But, sometimes when he didn't reply to my messages or didn't talk to me as usual, im going mad. I'll start thinking a lot..i will imagine that he is angry at me or avoiding me. I couldn't control my thoughts. I will repeatedly read his messages, word by word to check whether there is any indication of anger in that. Sometimes, if he doesn't reply to a message, i will repeatively send messages till he replies. But, then it turns out that, he is not having any problem with me as i thought. All would be my imaginations and fear. But next day every thing will start again..Sometimes i would try not to message him, to keep a distance. But couldn't hold for more than 4 days. Then i'll start messaging without any limit. I'm so much expressive and is disturbing him a lot...may be it would be bcoz of that, he is not messaging me, when im not messaging him...eventhough im a person who messages him everyday, he havn't shown any interest in messaging or asking me what happened during these 4 days. Sometimes, i will be deppressed when he didn't replies and bcoz of that tension, i'll get angry with my parents if they ask something during suchtimes. My mood will change suddenly if he calls or messages...i will be happy then..what will i do madam? What's my problem? I know that im paying over importance to him..what will i do.. Please tell me...