Learning to love myself? PLEASE READ AND HELPPP!?!

So I am 22, and I have been getting devastated over breakups since I was 15. I’ve always wanted a long term boyfriend, but I can never find love—so I filled that void with dancing, working hard in school, through my jobs (just currently got a job as a preschool teacher), the gym, reading, writing, friends, family, etc. (I even do these things when I am dating someone, so I know I’m not terribly clingy or anything). But I’m just at the point where being single makes me cry and feel miserable; I’m even becoming jealous of girls who do have boyfriends. Whenever a guy rejects me, I get depressed to the point where I am in bed for 14-18 hours at a time. My therapist told me that I need to spend this time focusing on who I am, what I want, and what makes me happy—she says that only when I learn to love myself, will I attract someone who loves and respects me. BUT if I do things to help myself (everything I listed above), and if everything I want and what makes me happy IS having a steady boyfriend, how am I supposed to follow her advice? And every other girl I know is always looking for a boyfriend, and I've girls get so much happier after they find somone, so my therapist's advice just confuses me more.What do you think?