Friend issues - bff replacing me
My best friend of 5 yrs has been talking to me less and less.
We used to message for hours after school and spend all of school together. This year she's got super close with another girl in her class and I barely even see her anymore as she spends all her time with this other girl instead. It's all happened so fast - I got her a present for her birthday a few months ago and she didn't get me anything last month or even mention it, other than texting me a happy birthday. I just feel shocked at the change - the last 5 yrs she's always been getting me great gifts with cards saying she's so thankful I'm her bff and this year literally nothing.
On the rare occasions I talk to her at school I feel she is deliberately making the conversations dry and doesn't want to talk to me and its always super awkward. I have felt she's kinda been dry with me in person for about a year but our relationship was weird during this time - we'd send voice notes online for hours but then barely speak in person unless in a group. So I felt that she did want to still be friends with me - I didn't feel like it was just me was clinging on to our friendship. But she doesn't even wave to me or acknowledge me around school in the corridors like she's embarrassed of me. Now we're doing exams so I'm not in school with her anymore and so I haven't spoken to her in weeks.
I genuinely don't know what to do I miss our friendship so much and am so confused on how fast it's completely crumbled. I don't feel either she or I have changed dramatically and on the occasions I do see her at school we laugh and have fun like we used to (although it feels slightly off and awkward). I just miss her friendship and don't know what to do about it since as school is done I genuinely have no contact with her. I could message her but it's so gut-wrenching reaching out first - like she doesn't feel the need to talk to me or miss me.
I don't have many other friends (maybe like 3 more?) but even with them I always feel kinda awkward and I know I'm not fully being myself but with my bff I always felt so comfortable - but now I don't even have that anymore. Going slightly off topic but I also feel like even though my friends like me I always feel like the least favorite friend and such a spare part; I'm always the one walking behind or sitting on the end of the row and for the last 3 summer breaks none of them reached out to me to hangout once. I know that I could've asked them but there's something so crushing about knowing that even if they say yes they didn't really want to hang out otherwise they would've asked. I also have crippling social anxiety and turn into an absolute mute around everyone else so I don't make friends easily. I just feel like with everyone I hang out with they don't actually want me there?
I don't mean to sound full of myself but I know I have a good personality: I'm funny and I've never argued with any of my friends ever and am always kind to everyone but clearly not enough? Please give advice with what to do with my bff (and friends in general) Thanks!! :)