Am i bisexual??

i am a 27 yr old girl,working. in my school days , i loved my best friend (girl) so much, she also loved me a lot. we had 4 yrs friendship, then gradually with life it lost.

two years back, i started loving a guy (was my classmate in college) very much. it was my first intense love with a guy..i was deeply in love with him. but he denied.it took 1 and half years to forget him. then i started loving 1 of my net friend (guy), i met him 2-3 times. but this didnt work also.

among my colleagues, there is a 23 yr old girl, who has become a good friend of me in several months, and coz she is a nice human being, i liked her. and gradually this liking intensifid, and now i understood i love her soo much. she has a stable boyfrind and i knew it from the beginning, then it was not a problem, but now i can't tolerate someone more important than me in her life. she also loves me , but i want to be the most important and mostly loved in her life. what is this?? it only happened with that school friend of mine.

one important thing to tell is...... i never felt any sexual/physical attraction to the girls i love.. i loved them by heart only..but the love is soo intense emotionally that it is painful for me not to have them for my whole life.on the other hand, i felt both sexual and emotional attraction to the guys i loved, and when i loved them, they were the only one i needed in my whole life.
so, it seems a persons biological sex (boy/girl) is not relevant for being in love for me... right? although i hv physical needs and always i fantasize about boys only. i never feelt doing sex with girls...so, its my situation.. and i am confused ...

1. what is my sexual orientation ? am i bisexual? if yes.. then does it mean only strong emotional love can determine someone's sexual orientation??

2. what should i do? i can't tell my problem to anyone.. they wont tk it normally.. and at the age of mine.. its problematic..

the present thing is i want to be with this girl all the time, share everything with her, love her and care for her so much, and want to be loved the most by her, and be the most important in her life.
and i hv started feeling very jealous to her boyfriend,, coz she loves him also and he is more important than me to her.

so, its very painful situation, i am unable to mix up freely with her... always thinking about this problem.. its eating me.. please answer my questions and help me..