Am I bi-sexual?

Hi,

I’m 15. I have never had a proper relationship with a boy. my longest one was with my friend who is a girl ( I am also a girl). it was for 3 months all we did was kiss. and this is the only girl I have sexual desires about. I have gotten as far a masturbation between me and a boy. and I do find boys cute, but have never loved one. I have only loved one girl. I got together with her when I was 14 for about 3 months and then when we broke up she went out with a boy and is still with him now and loves him. it breaks my heart. for the first 2 months of her relationship with her current boyfriend she said she still had some feelings for me but now she says she doesn’t. because she has had sex with her boyfriend and it is serious. she is the only person I felt comfortable kissing and holding in my arms. I love her. but I don’t know what to do because this is the only girl I think about sexually but then I haven’t ever loved a boy even though I do think about them too but it didn’t feel as nice as when I was kissing my girlfriend to when I kissed boys. am I bisexual?

please help me! thank you.

Confused.