I'm in love with my best friend
Are you positive that you are in love with your best friend?
I'm 100% sure, I've always been in love with him since high school.
It is okay to love someone even if they are your best friend. Plus it is good to talk about your feelings for someone.
I'm afraid that he won't love me back. What if I lose him?
That is a possibility. You can wait until you are sure he feels the same way back.Maybe jokingly flirt with him and see how he responds.