help: really confused - unsure if bi or not

hey Reddit,

this is my first post on this subreddit and had to make a fake account so hopefully no one tracks me down.

so it's been a few weeks now since I've accepted that I can be sexually attracted to guys (I'm a dude) and gosh I don't even know how to feel. I enjoy both straight and gay porn and I've known this for a while now, however... I always fantasize of being in a relationship with a girl, and never a guy. I also don't see how a relationship with a guy could work? I'm just in a very confused and stressed state right now with my sexuality in the midst of all the work I have for senior year of high school.

I think this might be because I'm surrounded by guys who do the same thing? always talk about girls? I also came out to one of my best friends a few weeks ago after I was kind of positive about being 'bi' but she didn't believe me and said I was just thinking too much, I took it back immediately and told her I was overthinking it (I'm not, I just knew she'd overthink it and eventually it might spread, that's not what I want...).

so my point is... how do I know if I'm bi? sounds like a stupid question yes but i know I'm sexually attracted to both genders, but not romantically. I've never came across a guy who attracted me, or made me think something could happen. What am I?! Ahhh!!!