i think my female cat was raped

i have a 9 year old female tabby who has 3 legs and she's super joyful usually but recently while i was away for work my sister brought a male cat over without my consent and left them there, i rushed back home from work and found my sister and the male cat gone and my tabby being super guarded. weeks pass by and she doesn't eat that much unless by hand and she's seems guarded, am i overthinking or did they fight? this is my first cat and I'm really wanting to help her.