Is it possible for feelings to change?

[Buring]

I knew this one lesbian who had always been lesbian, a real gold star...and then one day she meets a guy and she falls head over heels for him. As much as the thought annoyed me I thought maybe he was the "right guy" to make her straight. Well he turned out to be a total jerk who used and discarded her. And she never, ever (at least not while I knew her) fell for another guy. She still insists on calling herself bi over this one anomaly, however (I disagree, I think she's a lesbian).

I've heard of straights who had that one gay fling, too. And of course there's that popular game many hets have of who you would go gay for (listing which same sex celebrity you'd have sex with if the opportunity ever came up). So I'm betting these weird anomalies aren't as strange as they first seem.

Well is it possible I was bicurious...Or bisexual?
I just need an honest opinion, and I am deeply afraid my friends will all hate me for thinking I am toying with them...
I've only told people that I "felt" this and that to men, but some of my friends were all like "that's normal"

I don't know, I feel like the most messed up person in the world right now.
I mean, is it possible to find a girl that clicks with you like...Amazingly and even though you have feelings to men, to have same feelings for special woman and stuff.