Is it normal to not believe in love?

I have never been in love. I'm not even sure i believe in it. I don't believe in marriage, because no matter what eventually you fall out of love. This doesn't come from a family divorce. My parents are still together and don't have the kind of fights other families do.

I have never had a boyfriend I really liked. There was someone who I liked off and on for two years, but I stopped liking after we hooked up. He left for the rest of the summer and couldn't or wouldn't be my boyfriend. I know that was the logical thing to do I probably would have done the same thing, but it made me somehow think he didn't care about me enough. I have never liked someone as much since, and I never liked anyone as much before him. Is this a case of once bitten twice shy?

The problem is I have always had a problem letting people know I liked them romantically and even as a friend. I am never sure if people really like me or not. Sometimes I feel as if none of my friends really like me, and I am incredibly lonely. What the hell? Is there some kind of mental illness this qualifies for? Does anyone know why I'm like this?