I feel exactly the same. And not just love, but friendships too. The few friends i do have are the most beautiful, caring and sensitive people one could wish to meet - but when i'm with them, i often feel like i'm just taking advantage of their kindness. Also, i sometimes feel they just maintain contact with me out of pity, because i'm not a great friend, i'm extremely unreliable, i'm suspicious of people, and i feel i have nothing to offer people - no desirable traits, or anything. I haven't always been so shy and miserable - years ago i was quite a jolly, up-beat person. Sometimes i feel like they are just staying friends with me because they liked the person i used to be.
I feel that even if someone did like me, i'd just avoid them because a relationship with me would be very disappointing and boring for them - i don't enjoying going out and getting pissed, i don't enjoy going to restaurants and movies. Mostly, the things i enjoy are solitary activities. And i'm not a very warm person - it takes me ages to warm-up to people.
Also, i feel like if i did get into a relationship with someone, all their friends and relatives would dislike me. Does anyone else fear that?