Imagine your sister begging you to come to her college when yu graduate only for her to never want

I was going to choose a different college but then she convince me to come to the same college as her ... mind you i was already full ready to go to the other college ( i was accepted and my money was full paid). But I decided to go to her college because she always wanted me to be her company and do all different types of things with her ... so I went we shared a room ig ... on the first night when I moved in she went a way and leave me (i was scared and not expecting it ) then she came back in the evening the next day ... she did it again the next day ... at this point I was kind of upset ... but I did not say anything ... it would be like we are vibing and everything and then went to go and bathe then she was gone ... there was this one time where we went to a party and came back her bf came over with his cousin... I went to bathe and she him leave and the cousin stayed there I had no idea that she left it was only when I came out of the bathroom and then i see the cousin still there i was so uncomfortable i asked him to leave and did not want to leave ... i was upset and texted her to never do that again ... but it happened a second time and he did not want to leave i was soo tired at that that i went to sleep and then i was woken up to him having his hand in my clothes ... pushed him to leave until he left in the morning .. i told my sister what happen and she told me she did not kw he was there and that what he did was weird.. she said she talked to him and that he said sorry ... I was upset because ain't no way thats the only thing he had to say and same with my sister .... anyways on the weekends I started to go back home because I dont want to be here alone..
Idk how to feel ..