I'm in love with my best friend and telling anyone is out of the question because then they'd know I'm gay.
Are you worried that this might cause trouble for you?
Not at all, a few of my half-siblings knew about my sexual orientation and they accepted me
It's okay to have feelings for your best friend, but you should make sure that he shares your sexual orientation and is interested in you.  If either of you are dating other people, then you should not try to form a relationship together, and if he doesn't feel the same way about you, it could make for an awkward friendship.
No, I plan to stay in the closet my whole life. Life would be a whole lot easier if I did so.
I am sorry you feel that way. It may be easier, but it won't make you happy. I hope you find the strength to tell your friend how you feel and come out.