I hate that feeling in my heart

I hate that feeling in my heart when it like flutters. It always happens when I meet a douche of a guy and I can't stop talking to him and waiting for him to respond because I'm undesirable and clingy and he just starts to ignore me and it makes me wanna curl up in a ball and cry because he starts out interested and then after a few days, bam no more guy. Anyone else get this feeling?