My true love with another girl another girl i know a little too well?

okay so i fell in love with this guy lke madly in love with him no joke first love and i can feel it. so one day i was talking to him (hes a senior so hes going to graduate) and i confessed. i told him i loved him and that i wanted to never go a day without him. then he told me something odd. he said he was kind of taken. well he said he was in a serios relationship. i was devastated so that day after school i moped home and went to my sisters room to tell her the entire story. i busted in crying and i looked up to see my love having with my sister. i was torn apart how can i remove this black hole from my heart.