I'm never going to be happy...

Maybe love is not for me.. Maybe I'm suppose to be good at other thigs...but not love.. I can't do this anymore... I can-t run after a guy who tells me "I love you" and after he forgets that I exist... is to painful..i wonder... for how long do I continue like this. Sometimes I think it's been too log and other times i bealive it's worth fighting... But for how long? I'm aware that only I can stop this suffering... but why can't I stop? What keeps me going? All I know is that it hurts so f...ing much!