Aibu to not contact any friend

[Bbq1]

Have a friend I've known for around 18 years. We met at a past job, lost contact a bit briefly then I moved to a new place of work and she turned out to be there. We've both worked there for around 12 years now.As part of our job we were required to work closely for the first 2 years. We got on so well. After that our roles changed slightly so we weren't working closely but we would still sit together at lunch, eat out occasionally after work etc
Then I was off on long term sick for 2 years but we stayed in touch mutually. When I returned to work though I felt like something had changed between us, it was like we no longer had anything in common and she sat every lunch with a group or our much younger colleagues, talking about 'in' things and started going out with them socially. All fine but I felt totally sidelined. There was an incident where said friend hosted and organised a party for another colleague and I and another friend amongst other colleagues, only heard about it from people who had been. I wasn't bothered as I wouldn't have gone but still, it's nice to be asked by a longterm friend. Anyway, this continued up to lockdown. We're with currently off work for different reasons. A few weeks ago I thought I'll get in touch and see if we can have a chat just the two of us. I texted, she texted back that she'd call me the next day. She didn't. She then texted me a few days later to apologise that she had forgotten but would definitely phone on a day she named, she wouldn't forget this time. The day came and went and I heard nothing. That was about 3 weeks ago. I'm starting to feel like I am chasing her and don't want to really text her again. Should I just accept that this friendship has run it's course and assume she isn't really that bothered in keeping it.

[Bbq1]

Should have said my friend in the title