Almost everyone goes through little spurts where they aren't exactly 100% confident with their sexuality. This is nothing that you should worry about or take too seriously. Before you jump to the conclusion that you are bi-sexual, you should take the time to make sure that that is what you actually are, and it's not just your hormones playing a trick on you. Think about what it would be like dating a guy. Try and see if you can imagine yourself going through that, and if that is the type of thing that would make you happy. More than likely you just had a little feeling of curiosity, and it freaked you out.
If you keep having feelings like this, and you find yourself wanting to get more and more intimate with men, then you should consider your next steps, which would probably be experimenting.
Just whatever you do, realize that what you're going through is natural, and many other people go through the same thing.
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Hold me closer tiny dancer
Count the headlights on the highway