Am i over thinking?

I’m in year 13 but i’m upset at my best friend. She’s quite popular and i’m not mad that she’s popular but it just seems that we don’t hang out or doesn’t care much about me. She doesn’t respond quickly to my messages and may take days but she’ll be texting people on a groupchat so i know she’s active and free, she just can’t be bothered. Her responses are fine and she makes me laugh and she’s nice so it’s not like she’s a bad person. Idk the whole thing makes me angry especially if i’m next to her irl and i see her open her texts and she just hasn’t been bothered to open them?
She always says that we can walk up to school together and back home seeing as we live in the same town but there’s always someone that joins us on the way up or she stays behind after school to hang out with her other friends. Again I have no problems with this, but i would wait for her outside the school and call her like 5 times only to find out 10 minutes later that she will be staying at school - by then i’ve missed 2 trains and the next comes in half an hour. I do try and socialise with her friends but it’s clear they aren’t rlly fond of me and i don’t rlly catch onto what they’re saying bc pretty much all of them are on the same class. She always tells me that she’ll text me but she never does and she keeps telling me she forgets but the amount of times she forgets either makes me think that she’s dumb as rocks (which i know she isn’t bc she gets good grades) or she doesn’t care. This just makes me angry bc how hard is it to send me a text.
She’s not a bad person, i’ve known her for 14 years. I don’t want to tell her how i feel about this bc i never tell anyone how i feel and i could just be overreacting.
I hate it how I have to stand near her like a lost puppy when she talks to people i don’t know, then when i leave her, she asks why i did.
I just feel like everyone has that person that’s always be their side but mine is slowly disappearing. We’ve always been best friends and to see us separate just hurts. I could just be overreacting but this has just been annoying for the amount of times this has been happening. It almost makes me want to do the same back and make her suffer too, just so she can cry and experience what i’m feeling. But i’m not going to do that bc the second she cries, i know im gonna have people hating me and she is my friend after all . I do have friends that i could hang out with but it just doesn’t feel the same and i just hate school more and more.

I’m in year 13 but i’m upset at my best friend. She’s quite popular and i’m not mad that she’s popular but it just seems that we don’t hang out or doesn’t care much about me. She doesn’t respond quickly to my messages and may take days but she’ll be texting people on a groupchat so i know she’s active and free, she just can’t be bothered. Her responses are fine and she makes me laugh and she’s nice so it’s not like she’s a bad person. Idk the whole thing makes me angry especially if i’m next to her irl and i see her open her texts and she just hasn’t been bothered to open them?
She always says that we can walk up to school together and back home seeing as we live in the same town but there’s always someone that joins us on the way up or she stays behind after school to hang out with her other friends. Again I have no problems with this, but i would wait for her outside the school and call her like 5 times only to find out 10 minutes later that she will be staying at school - by then i’ve missed 2 trains and the next comes in half an hour. I do try and socialise with her friends but it’s clear they aren’t rlly fond of me and i don’t rlly catch onto what they’re saying bc pretty much all of them are on the same class. She always tells me that she’ll text me but she never does and she keeps telling me she forgets but the amount of times she forgets either makes me think that she’s dumb as rocks (which i know she isn’t bc she gets good grades) or she doesn’t care. This just makes me angry bc how hard is it to send me a text.
She’s not a bad person, i’ve known her for 14 years. I don’t want to tell her how i feel about this bc i never tell anyone how i feel and i could just be overreacting.
I hate it how I have to stand near her like a lost puppy when she talks to people i don’t know, then when i leave her, she asks why i did.
I just feel like everyone has that person that’s always be their side but mine is slowly disappearing. We’ve always been best friends and to see us separate just hurts. I could just be overreacting but this has just been annoying for the amount of times this has been happening. It almost makes me want to do the same back and make her suffer too, just so she can cry and experience what i’m feeling. But i’m not going to do that bc the second she cries, i know im gonna have people hating me and she is my friend after all . I do have friends that i could hang out with but it just doesn’t feel the same and i just hate school more and more.