You're struck with a sudden feeling of vulnerability, as you discover just how your body has changed over the course of one night. There's a vagina between your legs. Said legs have grown thicker in the wrong places, and your butt now round and soft, instead of toned and taut.
Unfortunately, that is not the only thing that has changed. The underwear in your closet in no way resembles what you remember buying yourself. Instead, there's an unusual amount of stringy lingerie, even some cutesy panties, and worse yet, some sexy underwear a little further back in the drawer, where you couldn't see it as quickly. The same went for your jeans, which had magically turned into a whole assortment of different legwear, with not only women's jeans, but also yoga pants, skirts, and even miniskirts, accompanied with stockings.
Your drawer for upper wear looked somewhat the same still, but even there, some regular T-shirts had simply been replaced with what you could only assume was more formal wear, shirts with buttons in them, to match with the skirts in his former jeans drawer.
The icing on the cake, however, was the massive poster that hung on his wall, of a famous European model, posing in front of a motorbike as part of an advertisement campaign for a motor vehicle company. You remembered her as a full-fledged woman, voluptuous figure, seated on the motorcycle with her butt jutted behind her and her back arched a bit, to increase appeal for male viewers like yourself. Where she used to have high heels that rested on the motor's pedals, now she's wearing large leather boots. Her shoes can actually touch the ground this time, and where her legs used to be bare, they're now covered by leather jeans. Her butt no longer sticks out, and has actually gotten smaller. Her legs have become more masculine, as if the opposite of your own.
And a quick search on the internet reveals more of these unmistakeable changes to you. The word 'woman' has gotten a whole new meaning, now that you discover that they can have both a penis and a vagina.
According to the internet, you are, by official standards, now a female man. That is, a man with female primary sex characteristics. No more penis and balls. There's a void where they used to be, hidden right between two meaty pussy lips and just behind a very sensitive little nub that sparked more arousal than you can remember ever feeling from your former cock.
There are more discoveries that make you feel queasy. Vaginal discharge is a thing that exists, and apparently scientists haven't come to a conclusion on whether squirting juice is actually pee or not. Periods occur every month, and you now know that the tampons are in the bottom drawer of the stand right by your bedside. Now it is you who can get pregnant, rather than your girlfriend, and as much as you like it raw, you know too much about the risks of unsafe sex for you to try it anytime soon. If anything were to go wrong, the pill right next to the box of tampons should do the trick.
By now, the musky scent of your... possibly urine, has spread across the room. You'll need to clean up your bed if you at least want to have some sleep tonight.
It takes ten minutes or so for you to replace the covers of your bed with clean ones from out of the closet. They've got an unfamiliar, albeit gender-neutral pattern on them, something you wouldn't have disliked, had your mother purchased them for you, even if you were still a guy.
You've replaced the thong you'd apparently worn to bed with a 'normal' set of panties, that feel a whole lot more comfortable and... a whole lot less revealing. For good measure, you decide to also wear a set of yoga pants for added protection for your increased vulnerability.
Sleep doesn't come easily, and you feel like it's going to require some time to adapt to whatever universe you've somehow managed to drop into.