Was I the bad friend?

I had a friend who was getting married and she had asked me to be the maid of honor but because she made a quick decision about the date (she was knocked up) my family and I were already set to go on a vacation so I had to decline. Well after that she kept making comments on her FB page about people being her "best friends" and such which started to irritate and hurt my feelings a bit. Then I found out that she didn't invite me to her bridal shower which I could have attended and I was planning on doing something for her since I did feel bad about not being able to attend he wedding. After that I un-friended her since I was tired of reading her posts and getting upset. She sent me a message and asked why I had done that and I told her I was upset about not being invited and she blew up on me. She went on and on about how crappy of a friend I was and how she only pretended to be my friend. I tried to be very "adult" about the whole back and forth thing and I didn't call her names or blame her for anything. I asked her if she wanted to try to continue to be friends or if she wanted to have just an amicable parting of ways and she said that she didn't pretend to like people she didn't really like and that she would walk the other way if she saw me in public. I know that it was stupid of me to have done the stupid FB un-friending but it was the first thing that I thought of doing since I was upset. I'll admit that I did let her know when I felt differently about something that she did but I did try to be there for her when she needed me but with a family of my own it can be difficult at times. I guess that I feel badly that our friendship which had lasted almost 20 years didn't seem to mean anything to her. I would have tried to put things behind us and resolve our differences and move on (I told her that) but she made it very clear that she wasn't interested at all. Was I wrong for not trying harder or did I do the right thing by letting her decide? Should I feel funny about seeing her in public? I've felt really bad about this for months now and I'd like to just move on.