how do i get back my friend circle now that i'm slowly losing all of them

I am 23 year old girl in uni and these days I can see that my closest friends do not interact with me except for the polite greetings. If I try to talk to them, they nod and reply and then move on with their other friends. Our classroom design makes sitting next to each other a bit difficult since there is a lot of space in-between, and that makes our interaction less frequent in class. But outside classroom, all of my friends ditch me for their own personal works. And these days my socials tell me that most of my friends and classmates are involved in many hangouts, uni programs, events, and projects. And I just feel left out since nobody informs me about these stuff, and I end up finding about them on socials. Whenever I'm sitting somewhere, nobody approaches me anymore to make small talk, they keep on hanging out with their other friends. My message inbox is now completely dry as well. I try to be nice, friendly, and try my best to interact with them- but i guess nothing works. I tried helping them with my notes, sending them posts on socials, approach them to smile and start a convo, offer them snacks, and joke around. Nothing works. As if I lost my charm and nobody likes me anymore. I'm not even involved in any romantic relationship that might cause problem.

What am I supposed to do? I don't want to be alone since I don't have any other friends outside Uni.