Why does it seem I always have fake friends?

I'm 16 this is gonna be my last year in high school and I'm gonna in the school year with no friends 👎🏽. It always seems like I have some fake ass friends and I wonder why is that. Me and my best friend had summer school together but honestly she started acting different with me out of no where. I was finishing my work so I wasn't paying attention to anything and she got up and left without telling me anything and I felt something of way but I didn't say anything and one time I was walking home with my friend and if he didn't say anything I wouldn't notice her while she was eating and I got mad because at least call my name or what not or text me where u at and I walked in the place gonna say hi to her and she gave me a dry ass hi and give me a dirty look. She tells me I'm fucking annoying thru text messages but I don't find my self annoying, I just want a real friend to text. Her brother got stabbed so he's in the hospital and I did text her the wrong time but I simply asked her what's her problem and this is what I get back