I'm stuck in a never ending cycle

I do this crazy thing where if I'm interested in someone I always think about other girls that are intrested in him too and how they are more suited to him than me. I always refer to them as "Genuine girls". Girls who are the center of attention and who are not afraid to say that they have an intrest in someone. Man I wish I had balls like them. I always clam up and come off as an up-tight bitch. I'm to scared to take a risk and put myself out there. I always get rejected and then I get all these others guys intrested in me that I have no intrest in. I know I sound cold, not giving them a chance at all, but I don't function like that. If I'm not physically attracted to you then there really is no chance. I'm like a guy. I think with my eyes and then my heart follows after. Anyways this is my endless cylce. I get intrested in someone, doubt that they could have an intrest in me too, then I meet a new guy and do it all over again. Someone help me stop this cycle! I don't wanna keep doing this through my 20s.