Why can't I get a boyfriend :( I don't know what I'm doing wrong..extremely ually frustrated!!!?

I am a 22 year old woman. And I haven't been able to find a boyfriend in three years--I've dated a lot casually to see if it leads to anything else, and I've been considered pretty, sweet, etc. by many guys, but it never turns out well. The guy is either terrified of commitment, "doesn't want to hurt me," feels like "I deserve better," or just plain ends up interested in another girl. It's frustrating. I just recently graduated college and work as a Preschool teacher, and plan on starting grad school in a few months. I enjoy dancing, yoga, reading, writing, and scrapbooking in my spare time, and have a lot of close female friends. But although all these things make me happy, they don't fill that void of having a relationship. I feel as though there is a huge gap in my life where someone special should be, and it's so frustrating to not be able to find that. I hate, HATE having no life (I don't want casual , it seems sleazy and unsafe to me), and I hate not having a guy in my life. Not only am I emotionally unfulfilled, I'm extremely ually frustrated. (A vibrator does not hold you, kiss you, etc. so that's not a good solution).I've even tried e harmony, and everyone I met on there was shady too haha. I don't know what to do--this is making so sad :( How to cope?