So I (18f) am on a gap year at the moment, mostly self-studying at home whilst the vast majority of my close friends are living out at uni. This means that I'm still in my home town whilst my friends are all over the country, so obviously we don't see each other much anymore since we're no longer at school/sixth form together everyday and most of them only come back to our hometown for the holidays every few months. As well as this, I'm no longer on any social media platforms - I strictly use text/WhatsApp to communicate with people now so understandably the frequency with which many of my friends talk to me has reduced. Having said that, whilst I do talk to many of my friends a lot less than before, it's still a reasonable amount and I don't feel as if our friendship is breaking down or that we're drifting apart - we'll send each other random things when something reminds us of the other person, or videocall for a couple hours when we both have the time, or even just send a quick text to let the other person know we're thinking of them and ask them how they're doing, etc.
However, there is one friend of mine who is honestly making almost no effort whatsoever to maintain our friendship, which strikes me as quite odd since (at the risk of sounding like a 5yo), we were literally best friends before. We were friends during GCSEs and got even closer in sixth form, to the point where in Yr13 we had no lessons or frees together yet we would both still make a HUGE effort to see and spend time with each other as much as possible. We were so close that everyone in our friendship circles knew that most Thursday lunches were reserved for us to go out for lunch and spend time solely with each other (which we would jokingly call our 'weekly dates') and a few of my friends even seemed mildly jealous of my friendship with her. We were also quite similar in personalities and had matching tastes/interests and we were both very physically affectionate as well so our friendship was really something special, at least in my eyes. But now everything seems to have changed and I'm not sure what caused it or how to move on. We tried to make plans to see each other a couple times last year but none of them ever worked out so I haven't actually seen her since we left sixth form - but I've seen almost all my other close friends, multiple times. Since then, she has also stopped responding to my messages except for once a month and the last time she messaged me a while ago she made a comment about how her lack of replies was completely her fault and that she wouldn't let our friendship end and asked if we could meet up over Easter to which I of course replied yes, but since then I haven't heard from her once in months, and I've messaged her many times since. Whenever I tried to call her, she never picked up or called me back - not even a text. It just feels so weird because I don't understand what went wrong between us. And if there's nothing wrong, how busy does someone get where they don't have time to text their best friend even once in months? Not even to tell me that she's busy and can't reply properly for a while? She even made a playlist for the two of us last summer which I've been listening to on repeat these last few days because I just miss her so much, but I'm also annoyed with her for just forgetting about me, like our friendship meant nothing to her.
If you read this far, I apologise that this was so long and rambley lol, I think I just needed to vent tbh but if anyone has any tips to get over a best friend breakup, or any words of advice at all really, I'd really appreciate it. Thanks again.