Lost?

Been away from Martin for 3 weeks and the feeling of insecure, being separated strike me again last Saturday. And it's getting worst nowadays. I figured out that i am overly fear of rejection and with no sense of belonging. I have lost all my confidence. How long will this feeling going to stay with me? I feel like i am a very sick person. I can't stay alone on myself. Otherwise, all these crazy/sick thoughts will come to me again. Should I go and see a doctor? Oh God, can someone help me please? :(