NO Friends

I have no friends. I am in my fourth semester in my first semester I have made friends but that friendship doesn't last long. It didn't ended on a bitter note just that they started ignoring me I don't know why and eventually left me. I am still in touch with them but not as group or that close bond is missing.Then I got another friend and she also dithched me for another girl in our class. I don't know why I am not understanding what is wrong with me. It is hurtful for me when I hear from someone that I am the problem of I have no friends. Like how I make friends how to make friendship last longer😭 I am sick of staying alone