Trust.

Is it human nature to feel lonely? What is this with everyone saying they are?
I feel at least it is a majority of people that complain about being completely surrounded by others and still feeling completely alone. My problem is feeling empty and in turn that makes me feel lonely. I just feel like no matter how I explain myself or try to get someone to understand me I just sound like a babbling hysterical fool. The loneliness I experience I feel is the loneliness I create for myself. I can be in an amazing relationship, have tons of friends, and genuinely be loved by others and I still think it's false. My problem is trust. I can never get myself to trust others. The pain runs so deep that I can't forgive and forget it. It's like a constant headache that wont go away. I will forget about it momentarily but it comes right back. Why can't I understand trust.