Need Some Advice

I started college like a year ago and it has not been going well if I had to express it in a word it was traumatic...Well I have had my fair share of bad experiences in friendship...for most of my life...I didn't really care and had a small friend circle...then Covid came and I lost contact with my friends and when we all came back to school again it was just awkward and not like before...for the next two years I was busy studying so I didn't care but then it was the last year of high school and I met a group of friends I was happy to feel included I enjoyed myself a lot with them until I realised I was just a backup friend they needed when they didn't have anyone else...and I was super late to realise this because I got involved in this friendship so much that it affected the other friendship I had, my grades went downhill, I became super insecure about things when I got out of it...I stopped believing in myself and regretted it...Fast Forward to when I entered college...for context I've never lived without my parents...it was the first time I was living in a dorm..with total strangers...in a place far away from my hometown....at first I was happy because my roommates all belonged to the same place I was from...things were good in the beginning but soon i don't know what happened...so I had 3 other roommates...my bedmate always never there in the room so I tried to befriend the other two ...it was good in the beginning but soon one of them let's name them A ...so A started pointing out everything I did and interrupted conversations with didn't involve them I was fine with it at first but it started getting irritating so I would stop talking to them ....it lasted a few days but I would start speaking again when I felt like I am calm enough to not talk back or get angry...but it continued happening and her bed mate let's call her B..B would always support A even though what she did was wrong... I did not understand why this was happening..it's not like they knew each other from before or anything like that..I tried to mend things...i would talk with them and ask them what their first impressions of me was or did they like me or not...but they would always answer in a very unusual tone... Things literally took a bad turn after six months, we totally stopped talking like in a room of four I was on one side while the others were on the other they would shout and talk loudly when I was trying to sleep ...they totally disrupted my mental health I didn't know where everything went wrong..I have had friends but I don't really like people I know to know how vulnerable I am so I refused to share this with anyone I know...and it's kind of like a burden to me...