I don't know how to be alone without feeling lonely

I've had a few groups of friends, this year it was a whole new class where I didn't know anyone, I was really anxious about it but it turned out well, I could find some people to be with on the first day of school and was really happy about it. Then we became a group but a few months later, the girl I had more nerness with was slowly lefting me because she got closer to other girls and I started feeling alone.

I was with them at school but I was feeling alone so I stopped and started to be alone at school. I started to be with other 2 girls from the group who felt the same way but I just felt alone and didn't know what to do, I still don't. I have an internet friend, a girl who was my girlfriend a few months ao, she is the only one I can open up to.

I just feel that I need to learn how to be alone but just the idea of walking alone in the school hall or be alone where it's "supposed" to be with someone gets me anxious. I just start to get anxious thinkinh that everyone is looking at me even though they're not. I've been sad, lonely and I just want to learn how to be in peace with myself so I can be ok again.