Welcome to the forums. I'm so sorry to hear that you've had such a terrible time trying to make friends and don't feel worthy to anybody.
It sounds like you really want to get out there and find some new friends, but you do not make friends easily and others aren't making it easy for you either.
Summer Rose's suggestion to think about your interests and getting involved in that is a good one. Even if you don't make any good friends, it will at least mean you can still be involved in something. And hopefully, you can make a friend there.
Still, the school environment can be really hard to make friends in, especially if you're new and everybody already has their own groups. It can be helpful sometimes to look outside of school, even if it's something you can do in-school. I know it doesn't directly help the time spent at school, but perhaps it can help you get through the day if you know you have something later that you're looking forward to.
Making friends can be really tough because you have to put yourself out there and hope people like what they see. It can be easier, and certainly feel better, to find other things you're actually interested in and hope that people who like the same things will want to have a chat with you.
In the meantime, does your new school have a counsellor? I don't know how much more help they can be than your mum, but perhaps they would have some ideas also with helping your social life?