uni is important from day 1 you should force your self to speak to people make simply talk hi whats up where you from, i know the first week i'm looking my best in terms of clothing and tell myself i'm going to sit next to the boys. First thing look around and observe and sit the people you want to and talk about the course, coursework, where you going at lunch. its hard cause its kinda your fault you didn't engage with people from your course this makes it really hard. Once you know a couple of people they would introduce you to other people and you build making friends. i'm a boy i talk about girls to the boys making jokes and saying i like this girl.
One story a girl liked me in university and when it was group work time she saw me random girl in another city and said hi your from my course ant you and talked for 10 min then once group work we had to form teams randomly talk to me can i join your group and i said yea made me think you have to force yourself to speak and get along with people, funny thing is we dated after that and she had a crush on me, so put yourself in the girls position and force yourself to talk make funny comments and talk to people but be nice doing it. people didn't like me in class and talk bad about me behind my back f it who cares not everyone will like you.
change classes is one option if you don't like people in class talk to the student desk people or senior lecture but these people may not care
transferring is another option, this may be a difficult task but ask, if not then re-apply to another uni is the best option and easy to do
i was researching about another subject and saw you post on the side and thought i should support you