Option 2:
>After your transformation you're dumped, in your now very ill fitting clothing, on the side of the road in the middle of nowhere 
>eventually make your way to the authorities, you're not the first, and after a medical exam they break the bad news
>there's a chip in your brain. They're working on a way to remove it but... it could be a while. It's designed to alter you, every so subtly, into <Waifu TBD> by encouraging 'in character' behaviour
>the first few victims didn't even realise it was happening. It's nothing so obvious as painful shocks or orgasmic pleasure.
>No, instead they'd be sitting watching a horror movie, but the character they've become... she's kind of skittish and girly. Never the sort to watch this sort of thing. So the chip ramps up those stress chemicals. Not to panic attack levels, just enough to be unpleasant. Not even halfway through some tame teen slasher movie and she's so on edge she's no longer enjoying it and has to turn it off. Probably just writes it off as being already stressed after everything that's happened recently, but the next time she sits down to watch a movie, she thinks twice before clicking on a scary one.
>Or she'd be looking for something to wear. She's tried wearing her old outfits, tightening belts and swimming inside her now oversized t-shirts, but she feels a twinge of discomfort going out in public like that. But that's normal, right? It does look very slobby...
>So she caves and buys some girl's clothing. Just jeans and t-shirts. It feels... better, but she still doesn't feel quite comfortable in them. But that's normal too, right? They fit differently to what she's used to. She'll get used to them in time.
>But of course, she never does. They always feel... just a little bit uncomfortable. Like wearing a suit and tie on a hot day. She frowns when she looks in the mirror... but that's just because she doesn't want to see a girl in it, right?
>Then, during some late night internet browsing, it happens. An ad for a cosplay store selling the outfit of the character she's been turned into. Probably there from all the research she's been doing about just who those weirdos turned her into, but... she feels drawn to it. Maybe she wouldn't have done this during the bright light of day, but sleep deprived at 4AM? She places the order.
>Once it arrives she knows something is wrong. Standing in the mirror, fully dressed as Hatsune Miku or whatever, the only negative thought in her head is "god damn it I wish I didn't get those twin tails cut, they're going to take forever to regrow"
>She feels comfortable in this outfit. She feels good about being seen in it. And she's convinced now it's a foreign influence, and that she can't let it beat her.
>But... maybe if she experiments a little... Games the system, beats them at their own game... She has more orders to place.
>It takes some trial and error, but she finds that she can get away with wearing normal clothing just fine. She feels almost as good in it as the costume and doesn't look ridiculous going out in public. It feels like a huge win, like she's gotten one over on the people doing this to her.
>As she steps out the door in her cute skirt and shimapan she's blissfully unaware every outfit in her new wardrobe would be perfect for some "casual Miku" alt art.
>but forewarned about what happened to the girls that came before you, you won't let the chip get to you, right?
>not even when, bored at home one evening (none of your hobbies seem to distract you the way they used to any more...) you stare at Megumin in the mirror and, just to try it, utter the catchphrase...
>there's no actual explosion, obviously, figuratively or literally. No waves of pleasure. But you do smile to yourself, maybe strike some 'cool' poses since you've already come this far. There's no harm just goofing around a little, making the most of this body now that you're stuck with it. It's not like anyone is MAKING you do this stuff. Everything will probably work out fine...