Maybe you've put them off by partaking in so much "fun"
Seriously, maybe they've painted you as 'not girlfriend' material. Maybe stop acting so desperate and immature - looking for a boyfriend-and-anyone-will-do-so-long-as-they-want-to-be-a-boyfriend. Shouldn't you like a person and hope that turns into something, rather than just looking for *a* boyfriend? Irregardless, these things often happen when you're not actively looking for a partner and are happy being single anyway. Did for me