It must be *really* awful for Roko, considering that, unlike humans I've known, she's spent most of her life happy with *her* body, and it was basically inseparable from her mind, so she never had to develop coping mechanisms to deal with these feelings hitting her all at once.[1] This sudden onset has to be a huge shock that she's ill-equipped to handle. Though not the same, recently, I had to deal with having real emotions again, months after coming off all of my non-PRN psych meds, and not having felt anything except vaguely miserable and bitter for too many years to count. Over that time, I lost the ability to deal with actually being able to deal with feelings from elation to rage, to sorrow, and the broadside was just too much.
And I think that in Roko's case, the fact that her face and other bodily bits are probably engineered to be as identical as possible short of replicator technology only serve to exacerbate these problems, and also, again, with the completeness of the "newness". If, say, she had come to her current body in a "ship of Theseus" or "My Grandfather's Axe"[2] manner, she would feel fine, even if the end result, physically speaking was identical, because it was still *her* body the entire time, even if she needed a new arm/leg/head at various points.
[1] At least us meatbags dealing with those issues have, even if in a maladaptive manner tend to have a lifetime's experience.
[2] Although, more modern dwarfs might admit that it *might* be a Grandmother's Axe, having discovered multiple pronouns