I write stories and such and my main character in my story is a Guy who falls in love with his best friend a girl. After my friends read it they gave me a weird look mostly because I don't act like a Guy(I'm a girl) and I haven't told them im I am questioning my sexuality but even so they have been treating me differently now I'm afraid to say anything. (The reason its in aguy p.o.v.is because its hard to write for a girl liking a Guy for me)I hope this all makes sense...
It does however at your age your friends are just caring too much over the little details. A love story is a love story, and as a fun fact, I've noticed straight women tend to be really good at male gay love stories so no need to feel you have to write as a girl lead falling head over heels over the perfect man.
Are you sure you aren't just projecting something you are feeling onto them? Have you asked them why they are treating you differently? Writers write stories about opposite gender characters all the time. Most good writers usually try to avoid writing from the perspective of characters too much like themselves. Mary Shelly's Frankenstein Ursula LeGuin's The Wizard of Earthsea and J.K. Rowling's Harry Potter series All books or series about male protagonists, written by women. And that's just off the top of my head. Sorry for the speculative fiction bent there, if it's not your thing.