This is probably more of an ideological or philosophical debate than a pharmacological one, at least the homosexual vs heterosexual component of it, its well known that stimulants increase sexual desire. Personally I believe sexuality is a spectrum, and not just a two dimensional one, and we are all moving around on it throughout our lives(not to say these are necessarily large movements, as portrayed by your case).
You definitely aren't the only person who claims this or something like it has happened to them, I believe there was recently a high profile case of a British man claiming gabapentin made him gay which whose argument was countered by some celebrity doctor(can't remember which one) with the gabapentin lowering his anxiety about homosexuality allowing him to act on latent desires, which was extremely plausible to me. The really interesting part about it, is though the man claims the gabapentin is what is making him gay, and he has verified this by not taking gabapentin anymore and returning to being heterosexual, he chooses to continue taking the gabapentin and living a homosexual lifestyle because he is happier that way while maintaining the hard line that he isn't actually a homosexual. I literally laughed out loud when I heard that part.
Not really in the mood to go to deep here, but basically saying I think these feelings exist inside you whether you have been or are normally aware of them or not. And its totally plausible that you only have latent homosexual desires, which normally wouldn't surface(especially given your feelings about homosexuality), but the sexual priming accompanied with stimulant use brought them to the surface, but these aren't feelings that are being created whole cloth by stimulants. I believe the fact that you felt ashamed afterwards points towards the fact that your moral programming is preventing you from accessing and analyzing these emotions and desires while sobre, there is absolutely nothing to be ashamed of.
