Parents cat always hissing at me

(USA, vet accessible) My parents have a 5 yo female spayed cat who they got in September after my uncle (cats original owner) passed away. We have two other cats (12 yo F, 16 yo M) who the new cat gets along with fine, occasional hissing or swating but usually just indifferent to each other. The first time I (22 yo F) stayed at home for a few days was over thanksgiving there was no issues with the cat, but then over Christmas she started hissing at me when I came down stairs and my parents weren’t home. She would stand up from what she was doing and come up to me hissing until I walked away. However if my parents are home this doesn’t happen at all. She will come up to me and even walk on my lap. This behavior continued over spring break, and now I am back for a week and a half to watch the cats while my parents go to Switzerland. She already kind of started the behavior this morning. To be honest I just don’t know what to do. I do not approach her at all. I genuinely get scared and I have really bad anxiety and this whole thing makes me so anxious. In the past I always knew my parents would come home eventually so I’d be fine but once they leave tomorrow I won’t have that safety net anymore. I feel like I can’t even eat because she hisses and come towards me any time I go into the kitchen. I just don’t know what to do and I am debating driving to my house every day from my apartment to feed them and do litter boxes (30-45 min drive depending on traffic) so I don’t have to live with her. My parents know and they definitely care but they’ve never witnessed it and they just kind of say how she’s so weird and not to worry about it. Please help!