Need perspective on a friendship

[Warmworm]

My close friend has, for about a year now, been cancelling on me regularly. We're both busy and work different hours (me during the week, her at weekends). I realise it's hard to fit me in. It's hard for me to fit her in too.

Thing is, I often rearrange things or use flexi to finish work early, then she cancels at the last minute. This last time she's given me more notice, but the reason is that instead of coming out with me she's doing something else with her husband and another couple. I know I tend to take things personally but this just feels rude and I'm a bit crushed.

Normally I would read the signs and let the friendship slide (although I don't want to - I really like her). But she keeps asking me to meet up again, then 3 times out of 4 it doesn't happen! I'm sad and frustrated and a bit hurt.

I used to see much more of her when our kids were young. I did her a lot of favours like ferrying her kids around when they were doing the same activities as mine. These favours were rarely returned, but then I'm not really a favour asker. I started to say no sometimes and I guess it's since then she's been less available.

Do you think she's only keeping me hanging in case she needs me?