Am I bisexual?

I'm a 14 year old boy and I don't know if I'm bisexual or not. My whole life I've been attracted to girls, sexually and romantically. But recently I found out that sometimes when I look at the male genitalia I find it arousing, and I think I might be in love with my best friend, who is a male, but I'm not really sure. I can't really imagine myself kissing him or dating him and I don't really feel I guess... attracted to him. Unlike when it's with girls I don't feel the need to constantly check if he's online or text him if he is or the need to continue the conversation whenever we talk, nor do I miss him or constantly wonder if he is ok. But then sometimes when I talk to him or look at him I get the feeling of butterflies in my stomach, and other times I feel nothing. Yesterday I was aware of this and I didn't really think a lot about this or about him, but now I do because I'm stressed out and I don't really want any of this. I'm thinking that maybe this is a way that my body found to cope with a heartbreak that I just went through, or maybe it's puberty and hormones and all, but I'm still not sure and I kinda want this feeling to stop. I'm ok with being bisexual maybe in a couple years or so, but not right now, and not with him. It's weird because sometimes these feelings are non-existent and other times they're not.