Why do I care?

So, I just found out tonight that I'm not going to be in my friend's wedding in May. Now, you may wonder why I would care. I'm wondering why I care. Maybe it's the way I found out that bothers me. Maybe it's the promises over the years that I'd surely be in it. Maybe it's the way she hyped up her engagement. Maybe it's because I was one of only 5 people to get an email showing her wedding dress she'd just picked out. I honestly don't know what it is, in particular, that has unnerved me, but it's definitely something. Now, let's back up 16 years when we first met in 6th grade. Yep, that's right, 6th grade. We weren't instant best friends by any means, but we naturally gravitated that way. We were almost inseparable in high school and stayed very much in touch during college (unlike any other high school friends I'd had). Both of us being only children and only 32 days apart, we were like sisters. She was even in my wedding 4 years ago (almost to the day). But, now the time has come for her to get married and I'm nowhere to be found. I have to admit that we've not been nearly as close since I got married, but we've managed to see each other a few times a year, sending emails and pictures and such back and forth. And, I've never met the guy she's marrying. But, none of this lessens my pain. I got the disturbing email today. It was a link to her wedding website. Everything was going along smoothly until I noticed the tab that said "Wedding Party." I thought, "Is this her way of letting me know that I'm in the wedding?", seeing as she hadn't said a word to me about it since the big announcement 2 weeks ago. So, I clicked on the link...scrolled down...I wasn't listed...anywhere. Nope...I even doubled checked...I'm wasn't there. Talk about upsetting! Instead of letting me know that I would be in the wedding, this was her way of slapping me in the face. That's exactly how it felt. So, why do I care? If she's going to tell me this way, why do I want to be bothered with it? Why would I want to be bothered with having to buy a dress, go to the parties, smile and look pretty, etc., etc., blah, blah, blah? Because I've known her for 16 years, that's why! Because she was in my wedding! Because she'd always promised! Just more proof for myself that I should never, ever, ever let myself get so close to someone again. I will only end up getting hurt in the end. But, why do I care?