Hi Liam Lemon, welcome to the forums.
I'm sorry to hear that your "friends" are treating you like that and not including you. If it makes you feel any better, that's happened to me my whole life (I'm 20), online and in person.
By the sounds of it, those people sound like they're fake and don't want to be your friend, and personally I think you're better off without them. I know how hard it is because you've tried your best and you want to be friends with them but it just seems to be hurting and upsetting you.
I also know how hard it is to be lonely and make new friends, but perhaps it's worth a shot somehow. Do you have any places to meet people near you, anything you're interested in? Just a suggestion, entirely your choice.
Or perhaps if you have Facebook and if you're comfortable, you could search for some groups for things that you like, such as bands? There's heaps of groups on there and you can talk to people of all ages all around the world and build connections with them. Or of course you can talk on here, it's safe here. No pressure just suggestions.
I wish I could be your friend, but we can be friends on these forums right? I'm sorry that you're struggling but please remember that those people aren't worth your time, they're just fake and wasting your time, and you're too good for them. By the sounds of it, you have a good heart and you're a kind, caring person, and if they can't see that then that's their problem and you don't need people like that who make you miserable and have no time for you but they waste your time. You deserve much better than that.
I hope you can find some other people who are better for you and make you happy and include you rather than bring you down, I know how hard it is but you can do it, try to be strong (you sound strong already though) and push through, keep trying. I believe in you.
I'm always here if you'd like to chat with me on your thread or anywhere on the forums. I'm 20 and I know exactly how you feel, it's happened to me endless times throughout my whole life. Because I know how it feels, I'd never do the same to anyone. So you're welcome to be my friend on these forums if you would like to, I'm happy to talk to you.
I hope I and others can somehow support you and be your friend. I hope you feel better somehow, soon. I'm here for you. Please know that I care, and I feel sorry for you.
Love and hugs,